KR20170090715A - Apparatus and Method of fully distributed scheduling in D2D networks - Google Patents

Abstract

The present invention relates to link scheduling method and apparatus, which can search for D2D pairs capable of performing D2D communication, obtain each channel coefficient information of the searched D2D pairs, align the searched D2D pairs in a descending order, calculates a sum rate of transmission capacities of a case when k^th D2D pair is added in an aligned order of the searched D2D pairs, compares the sum rate of the transmission capacities of the case when k^th D2D pair with a sum rate of transmission capacities of a case when (k-1)^th D2D pair is added, and selects D2D pairs with the maximum sum rate of transmission capacities by considering the comparison result. Accordingly, the present invention can select the D2D pairs to maximize the sum rate of transmission capacities.

Description

[0001] The present invention relates to a method and apparatus for link scheduling in a direct-

The present invention relates to a technique for scheduling a communication pair between terminals in a direct communication situation between cellular mobile communication terminals.

Recently, direct communication (D2D: Device to Device) using cellular has attracted much attention because of the following reasons.

First, D2D communication can extend the coverage of cellular networks without the need for additional infrastructure such as base stations (BSs) and repeaters. Second, D2D communication can provide data service with higher data rate, lower delay, lower power consumption than conventional cellular communication. Third, the spectral efficiency can be improved by increasing the spatial reuse gain that allows simultaneous transmission of multiple D2D communication pairs within the coverage of the cellular network.

This advantage of D2D communication has led to standardization in 3GPP (3rd generation partnership project).

On the other hand, many academic researches have started to study D2D communication.

Typically, a method for reducing interference caused by sharing a radio resource of a cellular network in D2D direct communication, a method for solving the problem that cellular communication is not used by a radio resource occupied by D2D communication, a cellular communication and a D2D communication A method for sharing resources including radio resources and power allocation, a method for handling interference between D2D communication and cellular communication, and the like.

However, no studies have been conducted to perform scheduling of D2D pairs so that the sum rate is maximized previously.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a link scheduling method and apparatus in an inter-terminal direct communication network.

Specifically, the present invention provides a scheduling method and apparatus for searching for D2D pairs capable of D2D communication and selecting D2D frames that can maximize the transmission rate among the retrieved D2D pairs, .

According to an aspect of the present invention, there is provided a link scheduling apparatus in a direct communication network, comprising: a search unit for searching for a pair capable of device-to-device communication (D2D); A channel coefficient acquiring unit for acquiring respective channel coefficients of the searched D2D pairs; And arranging the searched D2D pairs in a descending order, setting a transmission capacity of a 0th D2D pair to 0, arranging the searched D2D pairs in order of k (k is a constant larger than 1) D2D (SINR) of a pair of the D2D pairs, and transmits the searched D2D pairs in k-th D2D pairs when the k-th D2D pair is added sum rate of the k-th D2D pair is compared with the sum of the transmission capacities of the k-pairs when the k-th D2D pair is added and the sum of the transmission capacities to the k-1-th D2D pair, If the sum of the transmission capacities when the pair is added is smaller than the sum of the transmission capacities when only the k-1th D2D pair is added, calculation of the transmission capacity to be selected by the D2D pair transmitting data only to the k-1th D2D pair Including wealth .

If the sum of the transmission capacities in the case where the k-th D2D pair is added is greater than the sum of the transmission capacities in which only the k-1-th D2D pair is added, the transmission capacity calculation unit may calculate the transmission capacity k 1, the sum of the transmission capacities when the k-th D2D pair is added is calculated again, and the sum of the transmission capacities when the k-th D2D pair is added and the sum of the transmission capacities when the k- It is possible to compare the sum of the transmission capacities again.

In this case, if the k-th D2D pair is added until the k is equal to the total number of the searched D2D pairs, the transmission capacity calculation unit adds the transmission capacity when the k-th D2D pair is added, , It is possible to select all of the searched D2D full pairs as a D2D pair for transmitting data.

In this case, when the searched D2D pairs are sorted in descending order using the complex channel coefficient, the transmission capacity calculation unit may multiply the channel coefficients of each of the searched D2D pairs by a power of two, You can sort by.

A method for link scheduling in an inter-terminal direct communication network according to an embodiment of the present invention includes: searching for a pair capable of device-to-device communication (D2D); Obtaining respective channel coefficient information of the retrieved D2D pairs; Arranging the searched D2D pairs in descending order using the channel coefficients; Setting a transmission capacity of the 0th D2D pair to 0; Determining a signal-to-interference-plus-noise ratio (SINR) of the searched D2D pairs in order of k (k is a constant greater than 1) D2D pair; Calculating a sum of the sum rates when the k-th D2D pair is added in the ordered order of the searched D2D pairs; Comparing the sum of the transmission capacities when the k-th D2D pair is added and the sum of the transmission capacities when the k-1-th D2D pair is added; And D2D for transmitting data only up to the (k-1) th D2D pair when the sum of the transmission capacities when the k-th D2D pair is added is smaller than the sum of the transmission capacities when the (k-1) As a pair.

If the sum of the transmission capacities when the k-th D2D pair is added is greater than or equal to the sum of the transmission capacities when the k-1-th D2D pair is added, the step And the subsequent steps may be repeated in the step of calculating the sum of the transmission capacities when the k-th D2D pair is added.

At this time, if the transmission capacity when the k-th D2D pair is added is greater than the transmission capacity when the (k-1) -th D2D pair is added until k is equal to the number of the retrieved D2D pairs, And selecting all of the searched D2D pairs as a D2D pair for transmitting data.

In this case, the step of sorting the searched D2D pairs in descending order using the channel coefficient may square the channel coefficients of each of the searched D2D pairs and sort the searched channel coefficients in descending order of size.

The present invention searches for D2D pairs capable of D2D communication, acquires respective channel coefficient information of the retrieved D2D pairs, sorts the retrieved D2D pairs in descending order using the channel coefficients, The sum of the transmission capacities when the k-th D2D pair is added is calculated, the sum of the transmission capacities when the k-1-th D2D pair is added is compared, and the D2D pair is selected D2D pairs that can maximize the total sum rate of the searched D2D pairs can be selected.

1 is a diagram illustrating a schematic structure of an inter-device communication network according to an embodiment.
2 is a diagram illustrating a configuration of an apparatus for scheduling an inter-device communication pair according to an embodiment.
FIG. 3 is a flowchart illustrating a process of scheduling an inter-device communication pair so that the sum of transmission capacities becomes maximum according to an embodiment.
4 is a diagram illustrating an algorithm for scheduling an inter-device communication pair such that the sum of transmission capacities according to an embodiment is maximized.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are only for the purpose of illustrating embodiments of the inventive concept, But may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, for example, "between" and "immediately" or "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", and the like, are used to specify one or more other features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

Hereinafter, a link scheduling method and apparatus in an inter-terminal direct communication network according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

1 is a diagram illustrating a schematic structure of an inter-device communication network according to an embodiment.

1, the inter-device communication network is composed of N D2D pairs and a base station 100, and the D2D pair includes a pair of transmitting devices 111, 121 and 141 and receiving devices 112, 122 and 142 .

At this time, the transmitting apparatuses 111, 121, and 141 and the receiving apparatuses 112, 122, and 142 share the same frequency band, and in order to avoid interference between the cellular communication and the D2D communication, Wireless resources can be used for dedicated use.

D2D communication may share either the uplink frequency band or the downlink frequency band of the cellular network, but is more likely to share the uplink than the downlink. Therefore, in the D2D communication, the reference signal of the cellular uplink may be used for channel estimation or a separate reference signal may be used.

라 하며, 일반적으로 제로평균(zero mean)과 분산(

)과 함께 송신된다. 이때, 분산(

)은 경로 손실을 반영할 수 있다.In the present invention, the channel coefficient between the transmitting apparatus (i) and the receiving apparatus (j)

, Which is generally called zero mean and variance

). At this time,

) May reflect path loss.

All of the receiving apparatuses 112, 122, and 142 can estimate the channel coefficients from the transmitting apparatuses 111, 121, and 141 based on the reference signals.

는 D2D 장치들의 송신신호 전력 대 잡음 전력의 비율로 정의하고, 이하의 설명에서 손실 없는 신호대 잡음비(SNR; Signal to Noise Ratio)로 칭한다. 또한 모든 장치(111, 121, 141, 112, 122, 142)는 동일한 SNR을 가진 것으로 한다.In the present invention

Is defined as a ratio of transmission signal power to noise power of D2D devices, and is referred to as lossless signal-to-noise ratio (SNR) in the following description. It is also assumed that all the devices 111, 121, 141, 112, 122, and 142 have the same SNR.

로 정의하면,

는 아래 <수학식 1>과 같이 표현될 수 있다.The decimal number (d) along with the corresponding N binary numbers

Lt; / RTI &gt;

Can be expressed as Equation (1) below.

[Equation 1]

The present invention can confirm the activity of the i-th D2D pair through a link scheduling algorithm.

로 주어지면, D2D 페어의 i번째 수신 장치의 신호대 간섭 및 잡음비(SINR; Signal-to-interference-plus-noise ratio)(

)는 아래 <수학식 2>와 같이 표현될 수 있다.The number (d) of D2D pairs transmitting the transmission data at the same time is

, The signal-to-interference-plus-noise ratio (SINR) of the i-th receiving apparatus of the D2D pair

) Can be expressed as Equation (2) below.

&Quot; (2) &quot;

Then, the sum of the sum rates of the D2D communication network for a given d can be expressed as Equation (3) below.

&Quot; (3) &quot;

If the channel gain from all transmission devices to the reception devices can be estimated by the reception devices and the channel gain estimated by the reception device can be transmitted to the base station, D2D pair of < / RTI > The optimal transmission capacity can be calculated as shown in Equation (4) below.

&Quot; (4) &quot;

Here, the number of transmitting apparatuses can be changed from 1 to N.

Equation (4) can be approximated by the following method, and a corresponding optimal average transmission ratio can be obtained.

가 점진적으로 낮아진다면, <수학식 3>의 전송 용량은 아래의 <수학식 5>와 같이 근사화 될 수 있다.if,

Is gradually decreased, the transmission capacity of Equation (3) can be approximated as Equation (5) below.

이고, 1과 비교할 때, 간섭

는 무시할 수 있기 때문에 <수학식 5>와 같이 근사화 될 수 있다. 그리고, <수학식 5>은

일 때 최대화 될 수 있다.here,

, And when compared to 1, interference

Can be approximated as shown in Equation (5). Then, Equation (5)

Can be maximized.

를 송신할 수 있도록 허용하는 경우, 아래 <수학식 6>과 같이 표현되는 최적의 전송 속도에 도달할 수 있다.All D2D pairs are data

It is possible to reach the optimum transmission rate expressed by Equation (6) below.

&Quot; (6) &quot;

가 점진적으로 높아지고, 다수의 D2D 통신 페어들이 데이터

를 송신하면, 대응하는 전송 용량의 합(

)은 아래의 <수학식 7>와 같이 근사화 될 수 있다.if,

And a plurality of D2D communication pairs are transmitted to the data

, The sum of the corresponding transmission capacities (

Can be approximated as shown in Equation (7) below.

&Quot; (7) &quot;

, 간섭이 존재하지 않고, 대응하는 전송률(

)은 아래 <수학식 8>과 같이 표현될 수 있다.On the other hand, if the i-th transmitting apparatus of the D2D pair transmits data alone

, Interference does not exist, and a corresponding transmission rate (

) Can be expressed as Equation (8) below.

&Quot; (8) &quot;

가 주어진 채널 이득에 대해서 일정한 동안에,

가 무한대가 되므로

가 무한대가 되기 때문에 <수학식 8>에서

는 <수학식 7>의

보다 항상 크다.In Equation (7)

&Lt; / RTI > is constant for a given channel gain,

Is infinite

Becomes infinite, &quot; (8) &quot;

Is expressed by Equation (7)

It's always bigger.

가 0(zero)이 될 때,

또는 무한대가 된다. 그러나 이 경우의 확률은 0과 같다.In Equation (7)

Is zero,

Or infinity. However, the probability of this case is equal to zero.

Therefore, one D2D pair is allowed to transmit data with a high transmission capacity.

If the highest channel gain is selected among the D2D communication frames, it can be expressed as Equation (9).

&Quot; (9) &quot;

Then, it is possible to reach the optimum transmission rate expressed by Equation (10) below.

&Quot; (10) &quot;

2 is a diagram illustrating a configuration of an apparatus for scheduling an inter-device communication pair according to an embodiment.

2, a link scheduling apparatus 200 according to the present invention includes a control unit 210, a search unit 212, a channel coefficient acquisition unit 214, a transmission capacity calculation unit 216, a communication unit 220, (230).

The link scheduling apparatus 200 of the present invention may be configured to be included in the base station 100 or may be located outside the base station 100 and communicate with the base station 100. [

The communication unit 220 is a communication interface device including a receiver and a transmitter, and transmits and receives data by wire or wireless. The communication unit 220 can communicate with terminals (devices) to receive information of the D2D pair. The communication unit 108 performs a function of transmitting / receiving a radio signal of data input / output through an antenna (not shown). For example, in the case of transmission, channel coding and spreading are performed on data to be transmitted, RF processing is performed for transmission, and in case of a receiver, the received RF signal is converted into a baseband signal And performs a function of de-spreading and channel decoding the baseband signal to recover data.

The storage unit 230 stores an operating system, an application program, and storage data for controlling the overall operation of the link scheduling apparatus 200, and stores the D2D pair information, the SINR of the D2D pair obtained or calculated, Transmission rate (sum rate) information, and the like. The storage unit 230 may be a storage device including a flash memory, a hard disk drive, and the like.

The search unit 212 communicates with the devices through the communication unit 220 to search for a pair capable of device to device (D2D) communication.

The channel coefficient acquisition unit 214 receives or acquires the respective D2D pairs through the communication unit 220.

The transmission capacity calculation unit 216 arranges the D2D pairs searched in the descending order using the channel coefficients, sets the transmission capacity of the 0th D2D pair to 0, and sets the searched D2D pairs to k (k is larger than 1 (SINR) of the first D2D pair and determines the D2D pairs to be searched in order of the sum of the transmission capacity when the kth D2D pair is added ), And compares the transmission capacity when the k-th D2D pair is added and the transmission capacity when the k-1-th D2D pair is added, and if the transmission capacity when the k-th D2D pair is added is k-1 Th D2D pair is added, it is selected as a D2D pair transmitting data only up to the (k-1) th D2D pair. A method of calculating the SINR of the k-th D2D pair and the transmission capacity when the k-th D2D pair is added will be described later in more detail with reference to FIG.

If the transmission capacity when the k-th D2D pair is added is greater than the transmission capacity when the (k-1) -th D2D pair is added as a result of the comparison, the transmission capacity calculation unit 216 increments the value of k by one, It is possible to recalculate the transmission capacity when the pair is added and to compare the transmission capacity when the kth D2D pair is added and the transmission capacity when the k-1th D2D pair is added.

If the transmission capacity when the k-th D2D pair is added is equal to or greater than the transmission capacity when the (k-1) -th D2D pair is added until k is equal to the number of the found D2D pairs, All of the detected D2D pairs can be selected as D2D pairs for transmitting data.

Meanwhile, when the D2D pairs searched using the channel coefficients are sorted in the descending order, the transmission capacity calculation unit 216 squares the channel coefficients of each of the retrieved D2D pairs, and arranges the channel coefficients in ascending order can do.

The control unit 210 may control the overall operation of the link scheduling apparatus 200. [ The control unit 210 may perform the functions of the search unit 212, the channel coefficient acquisition unit 214, and the transmission capacity calculation unit 216. The control unit 210, the searching unit 212, the channel coefficient obtaining unit 214, and the transmission capacity calculating unit 216 are separately shown for the sake of explanation. The control unit 210 may include at least one processor configured to perform the functions of the searching unit 212, the channel coefficient obtaining unit 214 and the transmission capacity calculating unit 216, respectively. The control unit 110 may include at least one processor configured to perform some of the functions of the searching unit 212, the channel coefficient obtaining unit 214 and the transmission capacity calculating unit 216, respectively.

Hereinafter, a link scheduling method in the inter-terminal direct communication network according to the present invention will be described with reference to the drawings.

3 is a flowchart illustrating a process of scheduling an inter-device communication pair so as to maximize transmission capacity according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the link scheduling apparatus of the present invention searches for all pairs capable of D2D (Device to Device) communication (310).

)를 절댓값 제곱하고, 절댓값 제곱한 채널 계수(

)의 크기가 큰 순서대로 정렬할 수 있다.Then, the link scheduling apparatus obtains channel coefficient information of each of the searched D2D pairs through feedback and signaling (312), and sorts the retrieved D2D pairs in descending order using the obtained channel coefficients (314). At this time, the link scheduling apparatus calculates the channel coefficients of each of the searched D2D pairs

), And a channel coefficient obtained by squaring a full value (

) Can be sorted in descending order of size.

Then, the link scheduling apparatus sets the transmission capacity of the 0th D2D pair to 0 and initializes it. The link scheduler also sets the value of k to 1 (316).

The link scheduling device adds the kth D2D pair (317).

Then, the link scheduling apparatus scans the searched D2D pairs in order of signal-to-interference (SINR) of each D2D pair from the first D2D pair to k (k is a constant larger than 1) plus-noise ratio (318). At this time, the SINR of the k-th D2D pair can be calculated by Equation (11) below.

 &Quot; (11) &quot;

는 내림차순으로 정렬된 D2D 페어들을 중에서 i번째 D2D 페어의 수신기에서 수신된 SINR을 나타내고,

는 송신신호의 신호대 잡음비(SNR; Signal to Noise Ratio)을 나타내고,

는 내림차순으로 정렬된 D2D 페어들 중에서 j번째 페어의 송신기와 i번째 페어의 수신기i 사이의 채널 계수를 나타낸다.here,

Represents the SINR received at the receiver of the ith D2D pair among the D2D pairs arranged in descending order,

Represents a signal-to-noise ratio (SNR) of a transmission signal,

Represents the channel coefficient between the transmitter of the j-th pair and the receiver i of the i-th pair among the D2D pairs arranged in descending order.

Then, the link scheduling apparatus calculates the sum of the sum rates of the D2D pairs from the first D2D pair to the kth D2D pair in the sorted order (320). At this time, the transmission capacity when the k-th D2D pair is added can be calculated through Equation (12) below.

 &Quot; (12) &quot;

는 내림차순으로 정렬된 D2D 페어들 중에서 k번째 D2D 페어가 추가된 경우 첫번째 D2D 페어부터 k번째 D2D 페어까지의 전송 용량의 합을 나타내고,

는 내림차순으로 정렬된 D2D 페어들 중에서 i번째 D2D 페어의 수신기에서 수신된 SINR을 나타낸다.here,

Represents the sum of the transmission capacities from the first D2D pair to the k-th D2D pair when the k-th D2D pair is added among the D2D pairs arranged in descending order,

Represents the SINR received at the receiver of the ith D2D pair among the D2D pairs arranged in descending order.

Then, the link scheduling apparatus compares the sum of the transmission capacities when the k-th D2D pair is added and the sum of the transmission capacities when the k-1-th D2D pair is added (322)

If the sum of the transmission capacities in the case where the k-th D2D pair is added is smaller than the sum of the transmission capacities in the case where the (k-1) -th D2D pair is added as a result of the comparison in step 322, As a D2D pair to transmit (324).

If the sum of the transmission capacities in the case where the k-th D2D pair is added is greater than the sum of the transmission capacities in the case where the (k-1) -th D2D pair is added as a result of the comparison in step 322, the link scheduling apparatus determines that k is equal to the number of D2D pairs (326).

As a result of checking in step 326, if k is not equal to the number of detected D2D pairs, the link scheduling apparatus increments the value of k by one (334), and returns to step 318 to perform a series of processes thereafter.

If it is determined in step 326 that k is equal to the number of the detected D2D pairs, the link scheduling apparatus selects all of the D2D pairs as a D2D pair for transmitting the data (330).

4 is a diagram illustrating an algorithm for scheduling inter-device communication pairs to maximize the sum of transmission capacities according to one embodiment.

Referring to FIG. 4, an approximate source code for scheduling an inter-device communication pair can be identified so that the sum of transmission capacities is maximized.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, controller, arithmetic logic unit (ALU), digital signal processor, microcomputer, field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing apparatus may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments 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 embodiments, 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. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI &gt; or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

200; Link scheduling device
210; The control unit
212; Search section
214; The channel coefficient acquiring unit
216; The transmission capacity calculation unit
220; Communication section
230; The storage unit

Claims (13)

A search unit for searching for a pair capable of device-to-device communication (D2D);
A channel coefficient information acquiring unit for acquiring respective channel coefficient information of the searched D2D pairs; And
Sets the searched D2D pairs in descending order, sets the transmission capacity of the 0th D2D pair to 0, sets the retrieved D2D pairs in order of 1 to k (k is a constant larger than 1) (SINR) of the D2D pair and determines the sum of the transmission capacities when the k-th D2D pair is added in the sorted order (sum and the sum of the transmission capacities when the k-th D2D pair is added and the sum of the transmission capacities when the k-1-th D2D pair is added are compared, and when the k-th D2D pair is added The D2D pair transmitting data only to the (k-1) -th D2D pair when the sum of the transmission capacities of the (k-1) th D2D pair is smaller than the sum of the transmission capacities of the
A link scheduling apparatus in a direct communication network between terminals.
The method according to claim 1,
The transmission capacity calculation unit may calculate,
As a result of the comparison, if the sum of the transmission capacities when the k-th D2D pair is added is greater than or equal to the sum of the transmission capacities when the (k-1) -th D2D pair is added, The sum of the transmission capacities when the k-th D2D pair is added and the sum of the transmission capacities when the k-th D2D pair is added and the transmission capacity when the k-1-th D2D pair is added are again compared
A link scheduling apparatus in a direct communication network between terminals.
3. The method of claim 2,
The transmission capacity calculation unit may calculate,
If the transmission capacity when the k-th D2D pair is added is greater than the transmission capacity when the (k-1) -th D2D pair is added, until the k is equal to the number of the searched D2D pairs, all of the searched D2D pairs Select as D2D pair to transmit data
A link scheduling apparatus in a direct communication network between terminals.
The method according to claim 1,
The transmission capacity calculation unit may calculate,
When the searched D2D pairs are sorted in descending order using the channel coefficient, the channel coefficients of each of the searched D2D pairs are squared and the sizes of the channel coefficients obtained by squaring the squared values are sorted in descending order
A link scheduling apparatus in a direct communication network between terminals.
The method according to claim 1,
The SINR of the k < th > D &lt;
Is calculated through Equation (13) below
A method for link scheduling in a direct communication network between terminals.
&Quot; (13) &quot;

here,

Represents the SINR received at the receiver of the ith D2D pair among the D2D pairs arranged in descending order,

Represents a signal-to-noise ratio (SNR) of a transmission signal,

Represents the channel coefficient between transmitter j and receiver I.
The method according to claim 1,
The transmission capacity in the case where the k-th D2D pair is added,
(14) < EMI ID = 14.0 >
A link scheduling apparatus in a direct communication network between terminals.
&Quot; (14) &quot;

here,

Represents the sum of the transmission capacities from the first D2D pair to the k-th D2D pair when the k-th D2D pair is added,

Represents the SINR received at the receiver of the ith D2D pair among the D2D pairs arranged in descending order.
Searching for a pair capable of device to device (D2D) communication;
Obtaining channel coefficient information of each of the retrieved D2D pairs;
Arranging the searched D2D pairs in descending order using the channel coefficients;
Setting a transmission capacity of the 0th D2D pair to 0;
Determining a signal-to-interference-plus-noise ratio (SINR) of the searched D2D pairs in order of k (k is a constant greater than 1) D2D pair;
Calculating a sum rate of transmission capacity when the k-th D2D pair is added in the ordered order of the searched D2D pairs;
Comparing the sum of the transmission capacity when the k-th D2D pair is added and the transmission capacity when the k-1-th D2D pair is added; And
The D2D pair transmitting data only to the (k-1) -th D2D pair when the sum of the transmission capacities when the k-th D2D pair is added is smaller than the sum of the transmission capacities when the (k-1) -th D2D pair is added, RTI ID = 0.0 &gt;
A method for link scheduling in a direct communication network between terminals.
The method according to claim 1,
Further comprising the step of increasing the value of k by one if the transmission capacity when the k-th D2D pair is added is greater than the transmission capacity when the k-1-th D2D pair is added,
The following steps are repeated in the step of calculating the sum of the transmission capacities when the k-th D2D pair is added
A method for link scheduling in a direct communication network between terminals.
9. The method of claim 8,
If the sum of the transmission capacities when the k-th D2D pair is added is greater than or equal to the sum of the transmission capacities when the k-1-th D2D pair is added until k is equal to the retrieved D2D pairs, Further comprising selecting all of the pairs as a D2D pair transmitting the data
A method for link scheduling in a direct communication network between terminals.
8. The method of claim 7,
Wherein the step of sorting the retrieved D2D pairs in descending order using the channel coefficients comprises:
The channel coefficients of each of the searched D2D pairs are squared, and the sizes of channel coefficients obtained by squaring the sum of squares are sorted in descending order
A method for link scheduling in a direct communication network between terminals.
8. The method of claim 7,
The SINR of the k < th > D &lt;
Is calculated through Equation (15) below
A method for link scheduling in a direct communication network between terminals.
&Quot; (15) &quot;

here,

Represents the SINR received at the receiver of the ith D2D pair among the D2D pairs arranged in descending order,

Represents a signal-to-noise ratio (SNR) of a transmission signal,

Represents the channel coefficient between transmitter j and receiver I.
8. The method of claim 7,
The sum of the transmission capacities in the case where the k-th D2D pair is added,
(16) < RTI ID = 0.0 >
A method for link scheduling in a direct communication network between terminals.
&Quot; (16) &quot;

here,

Represents the sum of the transmission capacities from the first D2D pair to the k-th D2D pair when the k-th D2D pair is added,

Represents the SINR received at the receiver of the ith D2D pair among the D2D pairs arranged in descending order.
A computer-readable recording medium having recorded thereon a program for executing the method according to any one of claims 7 to 12.

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