KR20230094923A - Interference analysis-based radio resource reconstruction system and radio resource reconstruction method in space-time and frequency domain - Google Patents

Abstract

The present invention relates to a radio resource reconfiguration method based on interference analysis in at least one CR user node constituting a CR network, which calculates the number and distribution of existing users existing in a spatial domain based on channel use state information doing; modeling an interference environment scenario based on the number and distribution of the existing users; Calculating an interference probability, which is a probability of having an interference effect on the existing user, based on the modeled interference environment scenario; determining whether the received power received by the existing user satisfies a preset interference protection criterion based on the interference probability; and controlling transmission power based on whether the interference protection criterion is satisfied. Accordingly, it is possible to increase the frequency utilization rate of an idle channel and to ensure service quality through spectrum resource management capable of mutual coexistence among small cells in which a plurality of CR users exist in the space-time and frequency domains.

Description

Radio resource reconstruction system and radio resource reconstruction method based on interference analysis in space-time and frequency domains

The present invention relates to an interference analysis-based radio resource reconfiguration apparatus and radio resource reconfiguration method, and more particularly, to an interference analysis-based radio resource reconfiguration method capable of increasing the frequency utilization rate of an idle channel and guaranteeing service quality through optimal radio resource management. It relates to a reconfiguration system and a radio resource reconfiguration method.

With the recent development of the Internet of Things (IoT), a paradigm shift in computing technology is rapidly taking place to effectively process the vast amount of data generated by various IoT devices. According to research institutes, Internet-connected IoT devices are expected to generate close to 79.4 zettabytes of data by 2025, which is essential for key end-end terminals, from smart devices to machines, sensors, and cameras that make up the IoT. Significant changes are expected.

Meanwhile, some predict that around 10% of enterprise-generated data is already processed outside a centralized data center or cloud, and that figure will reach around 75% by 2025. This centralized computing structure suggests that cloud computing has limitations in accommodating various IoT services such as smart factories, smart farms, and autonomous vehicles that require real-time processing.

Therefore, due to the risk of overloading cloud servers based on the exponentially increasing amount of data and network traffic, the computing shift from the existing remote cloud within the wireless access network to the network edge is expected to become a hot topic as a new paradigm.

Edge computing is a distributed computing paradigm that brings computation and data storage closer to the data source. When computing services are processed close to the terminal used by users, they can receive faster and more stable services and benefit from flexible hybrid cloud computing. be able to enjoy

In particular, it is effective in overcoming the problem of long waiting times required for real-time data processing and decision-making in smart factories using IoT, and has the advantage of supporting real-time decision-making through sensing data collection and analysis.

However, in a dynamic spectrum environment that requires machine type device (MTD) operation in real time, the limited frequency resources of edge computing cause frequent frequency handoffs and serious performance degradation due to interference with other networks of the same type. There is a problem that occurs.

Accordingly, radio resource distribution needs to be dynamically optimized based on time variation parameters such as channel state information. Therefore, conventionally, in order to infer idle channels in a dynamic spectrum environment, occupancy probabilities and state transition probabilities based on historical data representing frequency statistics are used to learn the usage patterns of existing users or to enable continuous communication without interference with the current users. To do this, a reactive handoff method based on frequency detection and a pre-handoff method using a backup channel list are used.

However, such conventional spectrum resource management has a problem in that it does not consider spectral radiation mask specifications for CR (cognitive radio) users in the frequency domain and various propagation characteristics of radio waves on channel paths between existing users and CR users in the spatial domain. There is no interference management that can efficiently cope with the increase in inter-cell interference signals due to the spread of small cells.

Therefore, there is a problem that a CR user using an idle channel with maximum transmission power may have a serious interference effect on an existing user existing in a band and area adjacent to a CR user, and frequent spectrum handoff operations may occur due to restrictions on use of the idle channel.

Korean Registered Patent Publication No. 10-0890832

The present invention has been devised to solve the above problems, and an object of the present invention is to increase the frequency utilization of an idle channel through coexistent spectrum resource management between small cells in which a large number of CR users exist in the space-time and frequency domains. It is to provide an interference analysis-based radio resource reconfiguration system and radio resource reconfiguration method capable of improving service quality and guaranteeing service quality.

In order to achieve the above object, a radio resource reconfiguration method based on interference analysis in at least one CR user node constituting a CR network according to an embodiment of the present invention includes time slots (time slots in which each channel is partitioned at regular time intervals). Calculating the number and distribution of existing users existing in a spatial domain based on channel use state information calculated for each time slot; modeling an interference environment scenario based on the number and distribution of existing users existing in the spatial domain; Calculating an interference probability, which is a probability of having an interference effect on the existing user, based on the modeled interference environment scenario; determining whether the received power received by the existing user satisfies a preset interference protection criterion based on the interference probability; and controlling transmission power based on whether the interference protection criterion is satisfied.

The controlling of the transmit power may include determining a parameter for reconstructing a radio resource included in the modeled interference environment scenario when the interference protection criterion is not satisfied; calculating transmission power capable of satisfying the interference protection criterion based on the determined parameter; and maintaining the calculated transmission power.

In addition, after the step of maintaining the calculated transmit power, the step of calculating the interference probability, the step of determining whether the interference protection criterion is satisfied, and the step of controlling the transmit power may be repeatedly performed for a preset period.

In addition, the radio resource reconfiguration method is a step performed before the step of calculating the number and distribution of existing users, in a backup channel list received from a CR master node constituting the CR network together with the CR user node. The step of sensing the spectrum of the priority channel to determine whether it is an idle channel and, if not the idle channel, performing spectrum handoff by changing to a next-priority channel, wherein the interference probability is calculated after maintaining the calculated transmission power. As a result of re-performing the calculating step and determining whether the interference protection criterion is satisfied, if the interference protection criterion is not satisfied, the step of performing the spectrum handoff may be re-performed.

Also, the step of determining parameters for reconfiguring the radio resources may be performed based on a genetic algorithm.

In addition, the interference environment scenario includes an interference transmitter, an interfered receiver corresponding to the existing user affected by interference by the interference transmitter, and an interference prevented transmitter that transmits power to the interfered receiver. In the modeling step, a propagation loss model according to radio resources including at least one of parameters of the interfered transmitter, the interfered receiver, and the interfering transmitter, a specific distance and position, topography, and features may be defined.

In addition, in the step of calculating the interference probability, the received power received by the interfered receiver is calculated, the interference probability is calculated based on the calculated received power, and the received power is calculated from the interfered transmitter. Desired Received Signal Strength (dRSS), which is received power flowing into a receiver, and Interfered Received Signal Strength (iRSS), which is received power flowing from the interfering transmitter to the interfered receiver, may be included.

In addition, the step of modeling the interference environment scenario and the step of calculating the interference probability may be performed based on a Monte Carlo algorithm.

Meanwhile, in a radio resource reconfiguration system including at least one CR user node and a CR master node constituting a CR network according to another embodiment of the present invention for achieving the above object, the CR user node constants each channel. The number and distribution of existing users existing in the spatial domain are calculated based on the channel usage state information calculated for each time slot divided into time intervals, and the number and distribution of existing users existing in the spatial domain an interference analysis unit that models an interference environment scenario based on the interference environment scenario and calculates an interference probability, which is a probability of having an interference effect on the existing user, based on the modeled interference environment scenario; and a radio resource reconfiguration unit determining whether the received power received by the existing user meets a predetermined interference protection criterion based on the interference probability, and controlling transmission power based on whether or not the interference protection criterion is satisfied.

In addition, the radio resource reconfiguration unit determines a parameter for reconfiguring a radio resource included in the modeled interference environment scenario when the interference protection criterion is not satisfied, and satisfies the interference protection criterion based on the determined parameter. The transmission power that can be transmitted is calculated, and the calculated transmission power can be maintained.

In addition, the CR user node calculates the interference probability through the interference analyzer after maintaining the calculated transmission power through the radio resource reconfiguration unit, and the received power received by the interference-affected receiver is the interference protection criterion. , and controlling the transmission power based on whether the interference protection criterion is satisfied may be repeatedly performed for a preset period.

The CR user node may include: a spectrum sensing unit sensing a spectrum of a priority channel in a backup channel list received from the CR master node; and a spectrum handoff performer that determines whether the channel is an idle channel based on the spectrum sensing result, and if the channel is not an idle channel, changes the channel to a next-priority channel to perform spectrum handoff.

In addition, the CR user node, after the process of maintaining the calculated transmit power in the radio resource reconfiguration unit, re-performs the process of calculating the interference probability through the interference analysis unit and the process of determining whether the interference protection criterion is satisfied. Result If the interference protection criterion is not satisfied, the process of performing the spectrum handoff in the spectrum handoff unit may be repeated.

Also, the radio resource reconfiguration unit may use a genetic algorithm to determine parameters for reconfiguring the radio resources.

In addition, the interference environment scenario includes an interference transmitter, an interfered receiver corresponding to the existing user affected by interference by the interference transmitter, and an interfered transmitter transmitting power to the interfered receiver, and in the interference analysis unit The modeling of the interference environment scenario of can define a propagation loss model according to radio resources including at least one of parameters and a specific distance and location, topography, and feature for the interfering transmitter, the non-interfering receiver, and the interfering transmitter. there is.

In addition, the interference analysis unit calculates received power received by the interfered receiver, calculates the interference probability based on the calculated received power, and the received power flows from the interfered transmitter to the interfered receiver. Desired Received Signal Strength (dRSS), which is received power, and Interfered Received Signal Strength (iRSS), which is received power flowing from the interfering transmitter to the interfered receiver.

According to one aspect of the present invention described above, by providing a radio resource reconfiguration system and radio resource reconfiguration method based on interference analysis, spectrum resource management capable of coexistence among small cells in which a plurality of CR users exist in time and frequency domains is provided. Through this, the frequency utilization rate of idle channels can be increased and service quality can be guaranteed.

1 is a diagram for explaining conventional spectrum resource management;
2 is a schematic diagram for explaining spectrum resource management in a radio resource reconfiguration system according to an embodiment of the present invention;
3 is a diagram for explaining the configuration of a radio resource reconfiguration system according to an embodiment of the present invention;
4 is a block diagram showing a specific configuration of the CR user node shown in FIG. 3;
5 is a block diagram showing a specific configuration of an optimization unit of a CR user node shown in FIG. 4;
6 is a diagram illustrating a process of setting an anti-interfering link and an interfering link in a radio resource reconfiguration system according to an embodiment of the present invention;
7 is a diagram for explaining an interference scenario by an interference transmitter in a radio resource reconfiguration system according to an embodiment of the present invention;
8 and 9 are diagrams illustrating a process of processing interference analysis in a radio resource reconstruction system according to an embodiment of the present invention;
10 to 13 are views for explaining a process for determining parameters for radio resource reconfiguration in a radio resource reconfiguration system according to an embodiment of the present invention;
14 is a diagram showing a radio resource reconfiguration method according to an embodiment of the present invention;
15 is a diagram specifically showing the radio resource reconfiguration method of FIG. 14, and
16 is a diagram for explaining the effect of the radio resource reconfiguration method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention which follows refers to the accompanying drawings which illustrate, by way of illustration, specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable one skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in another embodiment without departing from the spirit and scope of the invention in connection with one embodiment. Additionally, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. Accordingly, the detailed description set forth below is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all equivalents as claimed by those claims. Like reference numbers in the drawings indicate the same or similar function throughout the various aspects.

Components according to the present invention are components defined by functional division rather than physical division, and may be defined by the functions each performs. Each of the components may be implemented as hardware or program codes and processing units that perform respective functions, and the functions of two or more components may be implemented by being included in one component. Therefore, the names given to the components in the following embodiments are not to physically distinguish each component, but to imply the representative function performed by each component, and the names of the components indicate the present invention. It should be noted that the technical idea of is not limited.

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

1 is a diagram for explaining conventional spectrum resource management. The conventional spectrum resource management detects an idle channel through a backup channel list in time and frequency domains, and performs a quick handoff operation on the detected idle channel. do.

However, in the conventional case, there is a problem in that the spectral emission mask standard for the CR user node 100 in the frequency domain and various propagation characteristics of radio waves on a channel path between the existing user and the CR user node 100 in the spatial domain are not considered.

In addition, there is no interference management capable of efficiently coping with the increase in inter-cell interference signals caused by the proliferation of small cells of various sizes.

Accordingly, the radio resource reconfiguration system (hereinafter referred to as system 1) according to an embodiment of the present invention, unlike the conventional spectrum resource management that reflects only such time, is a small cell in which a plurality of CR user nodes 100 exist in the spatial domain. It is possible to provide an optimal radio resource reconfiguration technology capable of increasing the frequency utilization rate of an idle channel and guaranteeing service quality through spectrum resource management that enables mutual coexistence among devices.

2 is a schematic diagram for explaining spectrum resource management in a radio resource reconfiguration system 1 according to an embodiment of the present invention. As shown in the drawing, the present system 1 manages spectrum resources so that mutual coexistence with existing users (IU) is possible in the space-time and frequency domains. Specifically, referring to FIG. 2, the radio wave environment and Optimal radio resources can be reconstructed by optimizing the transmission parameters considering the frequency separation. Such optimal radio resource reconstruction can enable mutual coexistence by determining parameters that satisfy the interference protection criteria for the existing user (IU) based on the channel information transmitted in the inference process using the backup channel list.

3 is a diagram for explaining the configuration of a radio resource reconfiguration system 1 according to an embodiment of the present invention, FIG. 4 is a block diagram showing a specific configuration of the CR user node 100 shown in FIG. 3, and FIG. 5 is a block diagram showing the specific configuration of the optimizer 135 of the CR user node 100 shown in FIG. 4, and FIG. 6 is a block diagram showing interference avoiding links and interference in a radio resource reconfiguration system according to an embodiment of the present invention. A diagram showing a process of establishing a link, FIG. 7 is a diagram for explaining an interference scenario by an interference transmitter in a radio resource reconfiguration system according to an embodiment of the present invention, and FIGS. 8 and 9 are an embodiment of the present invention A diagram showing a process of processing interference analysis in a radio resource reconstruction system according to, and FIGS. 10 to 13 are a process for determining parameters for radio resource reconstruction in a radio resource reconstruction system according to an embodiment of the present invention. It is a drawing for explaining.

The system 1 configures a CR (Cognitive Radio) network including at least one CR user node (CR User, 100) and a CR master node (CR Master, 200).

To be able to coexist here, the CR network is IEEE 802.22. A base station using a TV white space (TVWS) band according to a wireless local area network (WRAN) standard may be an infrastructure-based CR network that controls IoT devices in church areas where it is difficult to support broadband access, but is not limited thereto.

At this time, the CR master node 200, which is each base station constituting a single wireless network, independently manages frequency resources within the CR network through database contact for self-coexistence between cells of the same type existing in adjacent channels and locations, and CR The user node 100 is a terminal under the management of the CR master node 200, and may opportunistically use idle frequency resources in the CR network. And this system 1 can be controlled through software (application) for performing the radio resource reconfiguration method.

To this end, each CR user node 100 transmits the sensing data that senses the channel state in the CR network to the CR master node 200 (① sensing data), and the CR master node 100 stores it in a database. forwarded and stored. In addition, the CR master node 100 receives history data representing statistical information in the CR network for a certain period from the database side (② history data), creates a backup channel list based on this, and stores it in the CR user node 200. ) side (backup channel).

In addition, the CR user node 200 performs spectrum sensing and spectrum handoff based on the backup channel list from the CR master node 100 during a certain period. At this time, as a result of spectrum sensing, if it is inferred that the corresponding channel is an idle channel, it is determined whether or not there is interference with an existing user (IU) existing in a channel and location adjacent to the idle channel, and if it is inferred that interference will occur, the idle channel is used. It is possible to derive transmission power that satisfies the interference protection criterion to prevent interference, and to perform communication with the derived transmission power.

To this end, the CR user node 100 may include a communication unit 110, a control unit 130, and a storage unit 120. The communication unit 110 is provided to transmit/receive various types of information with an external device including the CR master node 200, transmits sensing data from the spectrum sensing unit 131 to the CR master node 200, and transmits the CR master node 200 side. A backup channel list may be received from the node 200 . The storage unit 120 is provided to store information transmitted/received or generated from the communication unit 110 and the control unit 130, and software (application) for performing a radio resource reconfiguration method may be stored in the storage unit 120. there is.

The controller 130 may include a spectrum sensor 131 , a spectrum handoff performer 133 , and an optimizer 135 .

The spectrum sensing unit 131 may generate sensing data that is channel state information by sensing the spectrum for a predetermined period. The sensing data generated in this way can be used to generate a user activity pattern representing statistical characteristics of the user in the time and frequency domains. The spectrum sensing unit 131 may sense the spectrum of a priority channel in the backup channel list received from the CR master node 200 .

In particular, the CR user node 100 of the present invention includes a spectrum handoff performer 133 composed of an inference engine to perform spectrum handoff operation to another idle channel, thereby enabling continuous communication without disturbing existing users. can do.

More specifically, the spectrum handoff performer 133 determines whether the channel is an idle channel based on a result of sensing the spectrum of a priority channel in the backup channel list, and maintains the channel if it is an idle channel. Spectral handoff can be performed by changing

At this time, the spectrum handoff performing unit 133 performs the above-described process up to a preset number of times during a second cycle (inference cycle) following the first cycle (learning cycle) for the CR master node 200 to generate the backup channel list. It can be done repeatedly.

When the CR user node 100 uses the idle channel, the optimizer 135 prevents the CR user node 100 from having a serious interference effect on existing users so that the CR user node 100 uses the idle channel with the maximum transmission power or meets the interference protection standard. Satisfactory transmission power can be used.

Specifically, the optimization unit 135 may include an interference analysis unit 1351 and a radio resource reconstruction unit 1353.

When the spectrum handoff unit 133 identifies an idle channel, the interference analyzer 1351 identifies an idle channel in the spatial domain based on channel use state information calculated for each time slot in which each channel is partitioned at regular time intervals. The number and distribution of existing users can be calculated.

And the interference analysis unit 1351 includes an interference environment including a wanted transmitter, a victim receiver, and an interfering transmitter based on the number and distribution of existing users existing in the spatial domain. scenarios can be modeled.

Modeling of the interference environment scenario in the interference analysis unit 1351, referring to FIG. 6, parameters and specific distances for the wanted transmitter, the victim receiver, and the interfering transmitter and defining a propagation loss model according to radio resources including at least one of location, topography, and feature. Here, the interfering transmitter may refer to a CR user node 200 having an interference effect on an existing user device, that is, a victim receiver.

As a specific example, the parameters of the interfering link (top) and the interfering link (bottom) for simulation may be as follows.

In addition, the interference analyzer 1351 may calculate received power received by a victim receiver based on the modeled interference environment scenario, and calculate an interference probability based on the calculated received power.

The received power calculated by the interference analyzer 1351 is the desired received signal strength (dRSS), which is the received power flowing from the wanted transmitter to the victim receiver, and the incoming power from the interference transmitter to the victim receiver. Interfered Received Signal Strength (iRSS), which is received power, may be included.

To this end, the interference analysis unit 1351 may model an interference environment scenario based on a Monte Carlo algorithm and calculate an interference probability through this.

Interference analysis based on the Monte Carlo algorithm performed by the interference analysis unit 1351 calculates randomly generated samples related to propagation of radio waves based on input parameters applied to a specific interference scenario environment, and uses the calculated samples to generate interference between users. probabilities can be calculated.

The interference analysis unit 1351 may include a user interface unit 13511, an event generation unit 13513, and an interference calculation unit 13515.

The user interface unit 13511 configures parameters (eg, antenna height, transmission power, and center frequency) for interference sources (interference transmitters and receivers) and interference sources (interfering transmitters) in an interference environment scenario according to user definition. etc.) and a propagation loss model according to a specific distance and location, topography, feature, etc. can be defined.

Such an interference environment scenario can be divided into a victim link and an interfering link, as shown in FIG. 6 . A victim link defines an existing user in use at a specific location and time in a licensed band, and may be composed of a wanted transmitter and a victim receiver. Interfering link may refer to communication that temporarily occupies and uses an idle channel not used by an existing user at a specific time and location through an opportunistic frequency use method using CR technology in a licensed band, and an interfering receiver (Victim Receiver) and a plurality of interfering transmitters (Interfering Transmitter).

Meanwhile, the event generation unit 13513 may calculate the received power flowing into the victim receiver by performing a simulation based on the interference environment scenario generated by the user interface unit 13511.

In the interference environment scenario shown in FIG. 6, the event generating unit 13513 is a frequency separation defined by parameters, a spatial distance, the number of interfering transmitters, and a certain number of events by the interfering transmitters. dRSS, the received power from the Wanted Transmitter flowing into the Victim Receiver, and iRSS, the received power from the Interfering Transmitter, can be calculated through repetitive simulation.

)과 안테나 이득(

)을 정의하며 도심 내 피간섭 송신기(Wanted Transmitter)와 피간섭 수신기(Victim Receiver)간의 거리 및 불특정 다수의 장애 요소들로 인한 전파 환경을 고려한 경로손실(

)을 이용하여 하기의 수학식 1과 같이 dRSS를 산출할 수 있다. The event generating unit 13513 transmits power (transmission power for the wanted transmitter and the victim receiver constituting the victim link).

) and the antenna gain (

), and path loss considering the distance between the wanted transmitter and the victim receiver in the city and the propagation environment due to a number of unspecified obstacle factors (

) can be used to calculate dRSS as shown in Equation 1 below.

[Equation 1]

, 간섭 송신기(Interfering Transmitter)와 피간섭 수신기(Victim Receiver) 간의 거리와 전파환경을 고려한 경로손실(

) 및 간섭 송신기(Interfering Transmitter)의 전송전력을 이용하여 간섭 송신기(Interfering Transmitter)로부터의 수신전력인

를 하기의 수학식 2를 통해 산출할 수 있다. And, as shown in FIG. 7, the event generation unit 13513 generates unwanted pulses generated from imperfect pulse formation of the interfering transmitter and individual elements constituting the interfering transmitter among the factors generating interference in the frequency domain. Radiation component

, Path loss considering the distance between the Interfering Transmitter and the Victim Receiver and the propagation environment (

) and the received power from the interfering transmitter using the transmission power of the interfering transmitter.

Can be calculated through Equation 2 below.

[Equation 2]

+

+

+

+

으로 정의될 수 있다. In addition, the event generation unit 13513 calculates the sum of the received signal powers flowing into the victim receiver when there are n interfering transmitters operating in different channels and arbitrary locations. It can be calculated through Equation 3. here

can be defined as

[Equation 3]

을 계산할 수 있고 피간섭 수신기(Victim Receiver)에 대한 간섭 보호비

와 비교한다. As shown in FIGS. 8 and 9, the interference calculator 13515 uses the iRSS obtained from the Nth event having a dRSS (=C) value higher than the sensitivity of the victim receiver.

can be calculated and the interference protection ratio for the victim receiver

compare with

이

보다 큰 경우에는 'Good',

이

보다 작은 경우에는 'Interfered'로 간섭발생 유무를 확인하게 되며, 이와 같은 과정은 전체 N개 이벤트 동안 반복적으로 수행할 수 있다. 이벤트가 종료된 후에는 실제 이벤트 개수 중 간섭이 발생된

의 확률을 하기 수학식 4를 통해 최종적으로 산출할 수 있다. 이때 실제 이벤트 개수는 앞서 정의한 바와 같이 피간섭 수신기(Victim Receiver)의 민감도보다 높은 dRSS값을 갖는 이벤트 수를 의미할 수 있다. If the interference calculation unit 13515

this

'Good' if greater than

this

If it is smaller than 'Interfered', the presence or absence of interference is checked, and this process can be performed repeatedly for all N events. After the event has ended, the number of interferences out of the actual number of events

The probability of can be finally calculated through Equation 4 below. In this case, the actual number of events may mean the number of events having a higher dRSS value than the sensitivity of the victim receiver as defined above.

[Equation 4]

/

/

Meanwhile, the radio resource reconfiguration unit 1353 uses the interference probability calculated by the interference analysis unit 1351 as an input value to determine whether the received power received by the victim receiver meets a preset interference protection criterion. can

Also, the radio resource reconfiguration unit 1353 may control transmission power based on whether or not the interference protection criterion is satisfied.

Specifically, the radio resource reconfiguration unit 1353 determines parameters for reconfiguring radio resources included in the modeled interference environment scenario when the interference protection criterion is not satisfied, and determines the interference protection criterion based on the determined parameter. It is possible to calculate the transmission power that can be satisfied.

Further, the radio resource reconfiguration unit 1353 may maintain the calculated transmission power, and may use a genetic algorithm as shown in FIGS. 10 to 13 to determine parameters for reconfiguring radio resources.

Specifically, as described above, the genetic algorithm used for optimal radio resource reconstruction based on the interference probability result obtained by the interference analysis unit 1351 based on the Monte Carlo algorithm is a natural evolutionary process through biological modeling of handling variables. It is an optimization algorithm imitated. The basic feature of this genetic algorithm is that weak species that do not adapt in the scenario environment considered based on Darwin's theory of evolution are eliminated and strong species are highly likely to be left to the next generation.

This genetic algorithm structure consists of initial population generation, fitness evaluation, and basic genetic operators (reproduction, crossover, mutation). Accordingly, the radio resource reconstruction unit 1353 of the present invention may include an initial group generation unit 13531, a fitness evaluation unit 13533, and a genetic operation unit 13535.

10 is a diagram showing a process of performing an interference analysis using an initial group. As shown, the initial group generator 13531 has an initial group P(k) representing a group in k generation (k-th iteration number) is 2 It can be defined as a set of N chromosome individuals having a binary string value as follows.

는 i번째 염색체로서 탐색 공간상의 한 점을 나타내며, 본 발명의 초기 집단 생성부(13531)는 초기집단 P(k=o)생성을 위해 난수발생기를 이용하여 NL(=집단크기X염색체 길이)개의 이진 정수로 염색체를 초기화하는 무작위 초기화(Random initialization)방식을 이용할 수 있다. here

represents a point on the search space as the ith chromosome, and the initial group generation unit 13531 of the present invention uses a random number generator to generate an initial group P (k = o) to generate NL (= group size X chromosome length) A random initialization method that initializes chromosomes with binary integers can be used.

Meanwhile, as shown in FIG. 11, the fitness evaluation unit 13533 first performs a decoding process on each chromosome in the initial group, and performs an interference analysis using the input variable x converted into a phenotype. . Afterwards, it is substituted into the objective function F(x) to calculate how well the input variable x fits into the row through the fitness function.

를 더한 다음 그 역을 취하는 방법으로 하기의 수학식 5와 같은 적합도 함수를 이용할 수 있다. At this time, the fitness function should always be written in the form of a maximization problem and should not have a negative value. Accordingly, in the present invention, a constant suitable for the objective function F(x)

A fitness function such as Equation 5 below may be used as a method of adding and then taking the inverse.

는 모든 입력 변수 x에 대해

>0 관계를 만족시키는 상수로서, 이를 정할 때 항상 F(x)의 최솟값에서 f(x)가 과도하게 큰 값을 갖지 않도록 해야 한다. 그러나 세대 진행과 무관하여

를 고정하면 선택압(Selection pressure)이 떨어지기 때문에 본 발명에서는 적합도 스케일링(Scaling window)을 통해 세대가 진행됨에 따라 적응적으로 최적의 입력변수를 적용하도록 하였다. here

is for all input variables x

As a constant that satisfies the relationship >0, when setting it, always ensure that f(x) does not have an excessively large value at the minimum value of F(x). However, irrespective of generational progression,

Since the selection pressure drops when is fixed, the present invention adaptively applies the optimal input variable as the generation progresses through the scaling window.

를 사전에 알기 어렵기 때문에 경험과 실험결과를 바탕으로 충분히 작은 값을 갖는 것이지만 세대 진행과 무관하게

을 고정하면 후기 세대에서 선택압이 떨어지는 문제를 갖게 된다. Specifically, fitness scaling is performed in the real environment as described above.

Since it is difficult to know in advance, it has a sufficiently small value based on experience and experimental results, but regardless of the generation progress.

If , there is a problem that the selection pressure drops in later generations.

를 계속 변경해줌으로써 일관된 선택압을 유지할 수 있도록 하고, 사용된 집단의 수를 스케일링 윈도우

라고 하였을 때, 크기에 따라 3가지 스케일링 모드로 동작하도록 하며 이는 다음과 같을 수 있다. Accordingly, in the fitness evaluation unit 13533 of the present invention, the minimum value of the objective function in the past multi-generational group is determined.

It is possible to maintain a consistent selection pressure by continuously changing

, it operates in three scaling modes according to the size, which may be as follows.

가 7인 경우이며, 꼭 이에 한정되는 것은 아니다. In the table above, 7 is the minimum value of the objective function.

When is 7, it is not necessarily limited thereto.

Meanwhile, the genetic operator 13535 may sequentially perform reproduction, crossover, and mutation operations according to the suitability evaluation.

First, reproduction selects individuals in the group P(k) based on the fitness result to form a mating pool P(k+1). Such selection can allow the genes in a population to spread widely in the population in subsequent generations by eliminating the weak individuals in the population and selecting for the strong individuals. In the method of implementing the reproduction algorithm, there may be roulette wheel selection, tournament selection, ranking based selection, etc. In the present invention, a roulette wheel widely used in genetic algorithms Although the algorithm was used, it is not necessarily limited now and may be one of the various methods described above.

The roulette wheel algorithm can select and clone chromosomes from the previous population according to the size of the selection probability. However, since you cannot change the gene, it does not affect the change in the overall genotype in the population. In addition, there is a disadvantage that the optimal object may not be selected during the selection process due to the stochastic property.

Accordingly, the genetic operation unit 13535 of the present invention applies an elite strategy as shown in FIG. 12 as a way to compensate for this, and through this, the strongest individual in the group is passed on to the next generation without disappearing. can guarantee that

On the other hand, crossover in the genetic calculation unit 13535 randomly selects parent chromosome pairs from the crossover source and exchanges and combines the bits after the crossover point with each other to create offspring, and the calculation is repeated until the size of the parent group is the same. will do Methods for implementing such a crossover algorithm include one-point crossover, multi-point crossover, and the like. However, it is not necessarily limited thereto.

This one-point crossover method is often referred to as standard crossover, and as a basic operator of the genetic algorithm, the operation during one cycle can be divided into three stages as follows.

Through this reproduction and mating operation process, chromosomes with similar shapes are gradually evolved at the end of the generation. However, at the beginning of the generation, due to the lack of genetic diversity, it may fall into a sub-optimal solution or a dead corner. Therefore, as a way to solve this problem, mutation is used, and the gene operation unit 13535 can generate a crossover source using crossover and mutation, as shown in FIG. 13 .

These mutations play a role in preventing certain bits of all chromosomes from being fixed in the early generation by changing the bits in the chromosome based on the mutation probability, and can be divided into the following three stages.

In this way, the optimization unit 135 including the interference analysis unit 1351 and the radio resource reconstruction unit 1353 maintains the transmission power calculated through the radio resource reconstruction unit 1353, and then the interference analysis unit 1351 During a preset period, the process of calculating the interference probability, determining whether the received power received by the victim receiver meets the interference protection standard, and controlling the transmission power based on whether or not the interference protection standard is satisfied It can be done repeatedly.

In addition, the optimization unit 135 calculates the interference probability through the interference analysis unit 1351 after the process of maintaining the transmission power calculated by the radio resource reconfiguration unit 1353 and the process of determining whether the interference protection criterion is satisfied. As a result of re-execution, if the interference protection criterion is not satisfied, the spectrum handoff performer 133 may re-perform from the process of performing the spectrum handoff.

Therefore, the CR user node 100 according to an embodiment of the present invention infers an idle channel through spectrum sensing using a backup channel list, and if an existing user is detected, selects and senses a backup channel corresponding to the next priority. Through this, a rapid spectrum handoff operation can be performed.

In particular, the CR user node 100 of the present invention maintains the currently used channel and transmission power if the interference protection criteria are satisfied when using an idle channel with maximum transmission power, but if the interference protection criteria are not satisfied, the optimization unit 135 By deriving and maintaining transmission power that satisfies the interference protection criterion through optimal radio resource reconfiguration, it is possible to enable mutual coexistence among small cells in which a plurality of CR users exist.

반복 수행될 수 있다. If the interference protection criterion is not satisfied even though the derived transmit power is maintained, the CR user node 100 selects the next backup channel and performs the above processes again, and these processes are performed at a preset inference period.

can be repeated.

According to the present invention, unlike the conventional spectrum resource management that reflects only time, spectrum resource management that enables mutual coexistence with existing users is possible by considering the spatial domain as well as the frequency, thereby increasing the frequency utilization rate of idle channels. In addition, it is possible to optimize transmission parameters considering the propagation environment and frequency separation.

Meanwhile, FIG. 14 is a diagram showing a radio resource reconfiguration method according to an embodiment of the present invention, FIG. 15 is a diagram specifically showing the radio resource reconfiguration method of FIG. 14, and FIG. 16 is a radio resource reconfiguration method of the present invention. It is a drawing for explaining the effect of the method.

Since the radio resource reconfiguration method according to an embodiment of the present invention is performed on substantially the same configuration as the system 1 shown in FIGS. 2 to 13, the same components as the system 1 of FIGS. 2 to 13 The same reference numerals are assigned to, and repeated descriptions will be omitted.

A radio resource reconfiguration method based on interference analysis in a radio resource reconfiguration system including at least one CR user node 100 and a CR master node 200 constituting a CR network according to the present embodiment includes checking idle channels and Performing spectrum handoff (S110), calculating the number and distribution of existing users (S120), modeling an interference environment scenario (S130), calculating an interference probability (S140), It may include determining whether or not to satisfy (S150) and controlling transmission power (S160).

In the step of checking an idle channel and performing a spectrum handoff (S110), the CR user node 100 senses the spectrum of a priority channel in the backup channel list received from the CR master node 200 to determine whether it is an idle channel, If it is not an idle channel, spectrum handoff can be performed by changing to a next-priority channel.

In the step of calculating the number and distribution of existing users (S120), if idle channels are checked in the step of performing spectrum handoff (S110), the CR user node 100 divides each channel into regular time intervals. The number and distribution of existing users existing in the spatial domain may be calculated based on channel use state information calculated for each time slot.

In addition, in the step of modeling the interference environment scenario (S130), in the CR user node 100, based on the number and distribution of existing users existing in the spatial domain, a desired transmitter and a victim receiver And an interfering environment scenario including an interfering transmitter may be modeled.

In the step of modeling such an interference environment scenario (S130), at least one of the parameters for the wanted transmitter, the victim receiver, and the interfering transmitter, and a specific distance and location, topography, and feature A propagation loss model according to radio resources including one may be defined.

In the step of calculating the interference probability (S140), the CR user node 100 calculates the received power received by the Victim Receiver based on the modeled interference environment scenario, and based on the calculated received power, the interference probabilities can be calculated.

The received power calculated in the step of calculating the interference probability (S140) is the desired received signal strength (dRSS), which is the received power flowing from the wanted transmitter to the victim receiver, and the interfering transmitter (Interfering Transmitter). ), iRSS (Interfered Received Signal Strength), which is the received power flowing into the Victim Receiver.

Here, the step of modeling the interference environment scenario (S130) and the step of calculating the interference probability (S140) may be performed based on the Monte Carlo algorithm.

In the step of determining whether the interference protection criterion is satisfied (S150), the CR user node 100 uses the interference probability as an input value to determine the interference protection criterion in which the received power received by the victim receiver is preset. can be judged to be satisfied.

Subsequently, in the step of controlling the transmit power (S160), the CR user node 100 may control the transmit power based on whether or not the interference protection criterion is satisfied.

In the step of controlling the transmission power (S160), if the interference protection criterion is not satisfied, parameters for reconstructing radio resources included in the modeled interference environment scenario are determined in the CR user node 100, and the CR user The node 100 calculates transmit power capable of satisfying the interference protection criterion based on the determined parameter, and the CR user node 100 can maintain the calculated transmit power.

At this time, the step of determining parameters for reconfiguring radio resources may be performed based on a genetic algorithm.

In the CR user node 100, after the step of maintaining the calculated transmit power (S160), the step of calculating the interference probability (S140), the step of determining whether the interference protection criterion is satisfied (S150), and the step of controlling the transmit power (S160) may be repeatedly performed for a predetermined period.

At this time, after the step of maintaining the calculated transmission power (S160), the step of calculating the interference probability (S140) and the step of determining whether the interference protection criteria are satisfied (S150) are re-performed. As a result, if the interference protection criteria are not satisfied, CR In the user node 100, spectrum handoff may be performed again from step S110. A more specific flow of the radio resource reconfiguration method of the present invention is as shown in FIG. 15, and since it can be sufficiently inferred through the drawing, a detailed description thereof will be omitted.

16 is a result of comparing performance of spectrum resource management techniques according to whether or not the optimization of the present invention is applied during a handoff operation based on a backup channel list in order to evaluate performance of spectrum resource management. Referring to the figure, the part corresponding to Non-optimization in the graph is 18 idle adjacent to existing users due to interference when there are 255 IoT devices performing uplink with maximum transmit power (12.6dBm) in a total of 46 idle channels. It can be seen that the use of the channel is limited.

On the other hand, as in the present invention, when the transmission power of the interference transmitter is optimized to satisfy the criterion of less than 5% interference probability in 18 idle channels whose use is limited due to interference, an unwanted emission mask (radiation According to the frequency separation due to component), the transmit power that can coexist with the existing user is about 5dBm in the nearest channel and 10dBm in the second adjacent channel.

In addition, using 500 historical data per traffic environment, as shown in FIG. 16, as a result of checking the average spectral efficiency depending on whether or not optimization was applied for each time period, it was found that when optimization was applied, spectral efficiency was improved by using idle channels whose use was limited due to interference. Confirmed.

The radio resource reconfiguration method of the present invention may be implemented in the form of program instructions that can be executed through various computer components and recorded in a computer readable recording medium. The computer readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

Program instructions recorded on the computer-readable recording medium may be those specially designed and configured for the present invention, or those known and usable to those skilled in the art of computer software.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floptical disks. media), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like.

Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes such as those produced by a compiler. The hardware device may be configured to act as one or more software modules to perform processing according to the present invention and vice versa.

Although various embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and is commonly used in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible by those with knowledge of, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

100: CR user node 110: communication unit
120: storage unit 130: control unit
131: spectrum sensing unit 133: spectrum handoff performing unit
135: optimization unit 200: CR master node

Claims (16)

A radio resource reconfiguration method based on interference analysis in at least one CR user node constituting a CR network, comprising:
Calculating the number and distribution of existing users existing in a spatial domain based on channel use state information calculated for each time slot in which each channel is partitioned at regular time intervals;
modeling an interference environment scenario based on the number and distribution of existing users existing in the spatial domain;
Calculating an interference probability, which is a probability of having an interference effect on the existing user, based on the modeled interference environment scenario;
determining whether the received power received by the existing user satisfies a preset interference protection criterion based on the interference probability; and
and controlling transmission power based on whether the interference protection criterion is satisfied. According to claim 1,
In the step of controlling the transmission power,
determining parameters for reconstructing radio resources included in the modeled interference environment scenario when the interference protection criterion is not satisfied;
calculating transmission power capable of satisfying the interference protection criterion based on the determined parameter; and
A radio resource reconfiguration method comprising the step of maintaining the calculated transmission power. According to claim 2,
After the step of maintaining the calculated transmission power, the step of calculating the interference probability, the step of determining whether the interference protection criterion is satisfied, and the step of controlling the transmission power are repeatedly performed for a preset period. Resource reconstruction method. According to claim 2,
The radio resource reconfiguration method,
As a step performed before the step of calculating the number and distribution of the existing users, the spectrum of the priority channel is sensed from the backup channel list received from the CR master node constituting the CR network together with the CR user node to determine an idle channel. and, if the channel is not an idle channel, performing spectrum handoff by changing to a next-priority channel;
As a result of re-performing the step of calculating the interference probability and the step of determining whether the interference protection criterion is satisfied after the step of maintaining the calculated transmit power, if the interference protection criterion is not satisfied,
The radio resource reconfiguration method of claim 1 , wherein the step of performing the spectrum handoff is performed again. According to claim 2,
The radio resource reconfiguration method, characterized in that the step of determining parameters for reconfiguring the radio resources is performed based on a genetic algorithm. According to claim 1,
In the interference environment scenario,
An interfering transmitter, an interfering receiver corresponding to the existing user affected by the interfering transmitter, and an interfering transmitter transmitting power to the interfering receiver,
In the step of modeling the interference environment scenario,
A radio resource reconfiguration method characterized by defining a propagation loss model according to radio resources including parameters for the interfering transmitter, the non-interfering receiver, and the interfering transmitter, and at least one of a specific distance and position, topography, and feature. According to claim 6,
In the step of calculating the interference probability,
Calculate received power received by the interfered receiver, and calculate the interference probability based on the calculated received power;
The received power is
Characterized in that it includes desired received signal strength (dRSS), which is received power flowing from the interfering transmitter to the interfering receiver, and interfered received signal strength (iRSS), which is received power flowing from the interfering transmitter to the interfering receiver. A method for reconfiguring radio resources. According to claim 1,
The modeling of the interference environment scenario and the calculating of the interference probability are performed based on a Monte Carlo algorithm. A radio resource reconfiguration system including at least one CR user node and a CR master node constituting a CR network,
The CR user node,
The number and distribution of existing users present in the spatial domain are calculated based on the channel usage state information calculated for each time slot in which each channel is partitioned at regular time intervals, and existing users existing in the spatial domain an interference analysis unit that models an interference environment scenario based on the number and distribution of , and calculates an interference probability, which is a probability of having an interference effect on the existing user, based on the modeled interference environment scenario; and
A radio resource comprising a radio resource reconfiguration unit determining whether the received power received by the existing user satisfies a preset interference protection criterion based on the interference probability, and controlling transmission power based on whether the interference protection criterion is satisfied. reconstruction system. According to claim 9,
The radio resource reconstruction unit,
If the interference protection criterion is not satisfied, parameters for reconfiguring radio resources included in the modeled interference environment scenario are determined, and transmission power capable of satisfying the interference protection criterion is calculated based on the determined parameters; , Radio resource reconfiguration system, characterized in that for maintaining the calculated transmission power. According to claim 10,
The CR user node,
After maintaining the calculated transmit power through the radio resource reconfiguration unit, the interference probability is calculated through the interference analysis unit, and the received power received by the interfered receiver included in the interference environment scenario meets the interference protection criterion. The radio resource reconfiguration system characterized in that the process of determining whether the interference protection criterion is met and controlling the transmission power based on whether the interference protection criterion is satisfied is repeatedly performed for a preset period. According to claim 10,
The CR user node,
a spectrum sensing unit sensing a spectrum of a priority channel in a backup channel list received from the CR master node; and
The radio resource reconfiguration system of claim 1 , further comprising a spectrum handoff performer for determining whether the channel is idle based on the spectrum sensing result, and performing spectrum handoff by changing the channel to a next-priority channel if the channel is not the idle channel. According to claim 12,
The CR user node,
After the process of maintaining the calculated transmission power in the radio resource reconfiguration unit, the process of calculating the interference probability through the interference analysis unit and the process of determining whether the interference protection criterion is satisfied are re-executed, and as a result, the interference protection criterion is satisfied. If not, the radio resource reconfiguration system according to claim 1 , wherein the spectrum handoff unit performs the spectrum handoff again from the process of performing the spectrum handoff. According to claim 10,
The radio resource reconstruction unit,
A radio resource reconfiguration system characterized in that a genetic algorithm is used to determine parameters for reconfiguring the radio resource. According to claim 9,
In the interference environment scenario,
An interfering transmitter, an interfering receiver corresponding to the existing user affected by the interfering transmitter, and an interfering transmitter transmitting power to the interfering receiver,
Modeling of the interference environment scenario in the interference analysis unit,
A radio resource reconfiguration system characterized by defining a propagation loss model according to radio resources including parameters for the interfering transmitter, the non-interfering receiver, and the interfering transmitter, and at least one of a specific distance and position, topography, and feature. According to claim 15,
The interference analysis unit,
Calculate received power received by the interfered receiver, and calculate the interference probability based on the calculated received power;
The received power is
Characterized in that it includes desired received signal strength (dRSS), which is received power flowing from the interfering transmitter to the interfering receiver, and interfered received signal strength (iRSS), which is received power flowing from the interfering transmitter to the interfering receiver. A radio resource reconfiguration system that does.

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