KR101675484B1 - Method for controlling operation of base station in wireless communication system - Google Patents

Abstract

Disclosed is a method for controlling a plurality of base stations in a wireless communication system including the base stations. The method for controlling base stations according to the present invention may comprise the steps of: (a) receiving, by each of a plurality of base stations, first reliability information, related to transmission power transferred between the base station and at least one user terminal, from the user terminal adjacent to the base station; (b) receiving, by the base station, second reliability information, related to the number of activated ones of the base stations, from other base stations adjacent to the base station; (c) generating, by the base station, third reliability information, related to additional transmission power required as a number of user terminals connected to the base station increases, based on the first reliability information and the second reliability information; and (d) transmitting, by the base station, the third reliability information to the user terminals adjacent to the base station.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of controlling base station operation in a wireless communication system,

The present disclosure relates to a method of controlling base station operation that can minimize the consumption of the total network energy (e.g., transmit power) of a wireless communication system including a plurality of base stations.

The transmission power control schemes in the wireless communication system include an optimal central control scheme, a suboptimal central control scheme, and a distributed control scheme.

The optimal central control method is a method of selecting the most optimal transmission power by investigating the number of all cases, assuming that an ideal central controller exists in the system and all necessary radio channels and interference information are known. Such a central control scheme has an advantage of achieving optimum performance, but has a disadvantage that the overhead of the control signal is large and the computation amount for optimization increases exponentially when the system is large.

In addition, the sub-optimal central control scheme assumes that an ideal central controller exists in the system as in the case of the optimal central control scheme, and knows all necessary radio channel information. It is a method to decide sequentially. The suboptimal central control scheme has the advantage of lower computational complexity than the optimal central control scheme, but has a disadvantage of low control performance.

In addition, the distributed control scheme can determine the transmission power independently of each member of the system, and can be determined solely based on the surrounding environment information or cooperatively determined through a certain information sharing with neighboring communication nodes. This distributed control scheme is advantageous in that the control complexity is small because no separate control signal is present or minimized. On the other hand, compared with the central control scheme, compared with the optimal performance that can be achieved by the central control scheme, There is a disadvantage that the performance is greatly deteriorated. The background technology of the present application is disclosed in Korean Patent Publication No. 10-2010-0113262.

Disclosure of Invention Technical Problem [6] The present invention has been made to solve the above-mentioned problems of the related art, and it is an object of the present invention to provide a distributed control of base station operation that can exhibit optimal total network energy (transmit power) consumption performance, And a base station apparatus for performing the method.

In addition, the present invention has been made to solve the above-mentioned problems of the prior art, and a plurality of base stations mutually cooperatively exchange network connection information (reliability information) to decipher connection between a user terminal and a base station without a central control device A distributed control method of a base station operation that minimizes network energy consumption, and a base station apparatus that performs the method.

It is to be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

According to an aspect of the present invention, there is provided a method of controlling a base station, the method comprising the steps of: (a) determining whether each of the plurality of base stations has a first Receiving reliability information from neighboring user terminals of each base station; (b) receiving, by the respective base stations, second reliability information related to the number of active base stations among the plurality of base stations from another adjacent base station of each base station; (c) generating third reliability information related to the additional transmit power required by each base station by increasing the number of user terminals connected to the respective base station based on the first reliability information and the second reliability information ; And (d) each of the base stations transmitting the third reliability information to neighboring user terminals of the respective base stations.

According to an aspect of the present invention, there is provided a base station apparatus including a communication unit and a processor, the base station apparatus including a processor configured to generate a first reliability associated with transmission power between the base station apparatus and at least one user terminal, Performing third step of generating third reliability information related to the required additional transmission power by increasing the number of user terminals connected to the base station device based on the information and the second reliability information related to the number of base stations active in the plurality of base stations Wherein the communication unit comprises: receiving the first reliability information from an adjacent user terminal of the base station apparatus; Receiving the second reliability information from another neighboring base station of the base station apparatus; And transmitting the third reliability information to an adjacent user terminal of the base station apparatus.

(A) each of the plurality of base stations transmits first reliability information related to transmission power between the respective base stations and at least one user terminal to adjacent users of the respective base stations Receiving from a terminal; (b) receiving, by the respective base stations, second reliability information related to the number of active base stations among the plurality of base stations from another adjacent base station of each base station; (c) generating third reliability information related to the additional transmit power required by each base station by increasing the number of user terminals connected to the respective base station based on the first reliability information and the second reliability information ; And (d) transmitting, by the respective base stations, the third reliability information to neighboring user terminals of the respective base stations, the computer-readable recording medium having recorded thereon a computer- May be provided.

According to an aspect of the present invention, there is provided a communication system including a communication unit and a processor, wherein the processor is configured to transmit first reliability information related to transmission power between the base station apparatus and at least one user terminal, And the third reliability information related to the additional transmission power required by increasing the number of user terminals connected to the base station apparatus based on the second reliability information related to the number of the first reliability information, Receiving information from an adjacent user terminal of the base station device; Receiving the second reliability information from another neighboring base station of the base station apparatus; And transmitting the third reliability information to an adjacent user terminal of the base station apparatus.

The above-described task solution is merely exemplary and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, there may be additional embodiments described in the drawings and the detailed description of the invention.

According to any one of the above-mentioned objects of the present invention, network connection information (reliability information) is exchanged cooperatively between a plurality of base stations and user terminals without passing through a central control device, The performance of the entire network energy consumption can be exerted with a small amount of computation.

1 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.
2 is a conceptual diagram illustrating a state in which a plurality of base stations and a user terminal exchange reliability information through functionally defined virtual nodes according to an embodiment of the present invention.
3 is a flowchart illustrating a method of controlling a base station in a wireless communication system according to an embodiment of the present invention.
4 is a flowchart illustrating a method of controlling a base station in a wireless communication system according to another embodiment of the present invention.
5 is a flowchart illustrating a method of controlling a base station in a wireless communication system according to another embodiment of the present invention.
6 is a block diagram illustrating a base station apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms "about "," substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

The present invention relates to a method and apparatus for controlling and optimizing each member (node) in a wireless communication system including a plurality of base stations in a distributed manner without a separate central coordinator by controlling transmit power, resources, .

According to the present invention, each member (node) optimally corrects its transmission power, resources, and the like based on the reliability information (message information) received from peripheral members, State) can be determined. In addition, each member updates the message information received from the neighboring members and exchanges updated message information with neighboring members. The present process repeatedly repeats this process to induce the wireless communication system to reach an optimal state as a whole.

Further, the present invention is applicable to all types / types of wireless communication systems. For example, the present invention can be applied to cellular systems such as 3GPP-LTE, 4G LTE / LTE-A, and 5G communication systems, wireless LAN systems, object Internet systems, and automobile communication systems.

Hereinafter, a method of controlling a base station in a wireless communication system according to an embodiment of the present invention will be described in more detail.

1 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention. The number of base stations and user terminals to be interconnected in a wireless communication system is not limited, and a wireless communication system including three base stations and four user terminals, with reference to FIG. 1, A base station control method of a wireless communication system will be described.

For example, as shown in FIG. 1, the wireless communication system 10 may include a first base station 110, a second base station 120, and a third base station 130. The first user terminal 140, the second user terminal 150, the third user terminal 160, and the third user terminal 160 are provided around the first base station 110, the second base station 120, 4 user terminals 170 may be located.

Each user terminal 140,150,160,170 receives a reference signal from each of the base stations 110,120 and 130 and generates channel information of a network link with each of the base stations 110,120 and 130 based on the received reference signal (gain) and signal quality.

Each of the user terminals 140, 150, 160 and 170 may generate first reliability information related to transmission power and channel information between each of the base stations 110, 120 and 130 and each of the user terminals 140, 150, 160 and 170 and may transmit the first reliability information to each of the base stations 110, 120 and 130. The first reliability information is information related to the number of user terminals connected to each of the base stations 110, 120 and 130 and the transmission power required for network connection with the corresponding user terminal. The first reliability information is information related to each user terminal 140, 150, 160, And the likelihood or probability value for connection activation between the base stations 110, 120, and 130. [ The first reliability information may be generated by each user terminal based on reliability information (seventh reliability information below) related to the probability that each user terminal 140, 150, 160, 170 is connected to any one of the plurality of base stations 110, 120, .

Each of the base stations 110, 120 and 130 generates second reliability information related to the number of active base stations among a plurality of base stations included in the wireless communication system 10, and transmits the generated second reliability information to neighboring base stations 110, 120, . The second reliability information may be information indicating a preference or a probability value for activation of each of the base stations 110, 120 and 130 when considering the number of base stations operating in the active state among the plurality of base stations and the power consumption of the entire wireless communication system.

Each of the base stations 110, 120 and 130 may generate the third reliability information based on the first reliability information received from the adjacent user terminals 140, 150, 160, and 170 and the second reliability information received from the neighboring base stations 110, have. The third reliability information is information related to the additional transmission power required by increasing the number of user terminals connected to each of the base stations 110, 120 and 130. The third reliability information is information related to the additional transmission power required for each of the base stations 110, 120, May be information indicating a preference or a probability value for connection activation between nodes.

Each of the base stations 110, 120, and 130 may transmit the third reliability information to each of the user terminals 140, 150, 160, and 170 adjacent to the respective base stations. Each of the user terminals 140, 150, 160, and 170 receiving the third reliability information from each of the base stations 110, 120, and 130 may update the first reliability information based on the third reliability information.

The first reliability information, the second reliability information, and the third reliability information may be calculated as a probability value of 0 or more and 1 or less. Also, the first reliability information, the second reliability information, and the third reliability information may increase as the preferences for connection between the base stations 110, 120, and 130 and the user terminals 140, 150, 160, and 170 increase. The greater the preference for connection between the base station and the user terminal means that the decrease in the total transmission power or consumption of network energy in the entire wireless communication system is increased when the connection between the base station and the user terminal is activated.

Each of the base stations 110, 120, and 130 transmits fourth reliability information related to the required additional transmission power by increasing the number of active base stations and the number of user terminals connected to each of the base stations 110, 120, and 130 among a plurality of base stations included in the wireless communication system Can be generated. Considering the number of user terminals connected to each of the base stations 110, 120, and 130, the number of base stations operating in an active state among the plurality of base stations of the entire wireless communication system, and the amount of additional transmission power according to the number of user terminals connected to the base stations 110, ) Or a probability value for the activation of the control information. In addition, the BSs 110, 120 and 130 may exchange the generated fourth reliability information with neighboring BSs 110, 120 and 130.

In addition, each of the base stations 110, 120 and 130 generates fifth reliability information indicating the active state preference of each of the base stations 110, 120 and 130 based on the second reliability information and the fourth reliability information received from the neighboring base stations 110, 120 and 130 . The fifth reliability information may be information indicating a likelihood or a probability value as to whether each of the base stations 110, 120 and 130 is activated according to an increase in the number of active base stations with respect to the base stations 110, 120 and 130.

Also, each of the base stations 110, 120, and 130 may transmit the sixth reliability information related to the additional transmission power required by increasing the first reliability information received from the adjacent user terminals 140, 150, 160, and 170 and the number of user terminals connected to the base stations 110, 120, Can be generated. The sixth reliability information may be information having a preference degree or a probability value indicating the activation state of each of the base stations 110, 120 and 130.

The fourth reliability information, the fifth reliability information, and the sixth reliability information have a value between 0 and 1, and may increase as the preference for the activation state of each of the base stations 110, 120, and 130 increases. The increase in the preference for the activation state of each of the base stations 110, 120, and 130 indicates a degree of desirability of a certain base station to operate in an active state relative to other base stations, considering the transmission power amount or the network energy consumption amount of the entire wireless communication system May mean that the value becomes larger.

Each of the base stations 110, 120, and 130 may determine a base station operating in an active state among a plurality of base stations based on the generated fifth reliability information and sixth reliability information. Specifically, each of the base stations 110, 120, and 130 calculates a sum of the fifth reliability information and the sixth reliability information. In addition, each of the base stations 110, 120, and 130 determines to activate a base station having a sum of the fifth reliability information and the sixth reliability information having a value greater than zero.

Also, the first reliability information and the third reliability information may be generated for a one-to-one connection relationship between each of the base stations 110, 120, and 130 and neighboring user terminals 140, 150, 160, and 170. Each of the base stations 110, 120 and 130 calculates a sum of the first reliability information and the third reliability information with respect to a one-to-one connection relationship between each of the base stations 110, 120 and 130 and adjacent user terminals 140, 150, 160 and 170. In addition, each of the base stations 110, 120 and 130 may determine to activate the connection between the base station and the user terminal, the sum of the first reliability information and the third reliability information being greater than zero.

In addition, each of the base stations 110, 120 and 130 generates the fifth reliability information and the sixth reliability information after the generation and mutual exchange of the first reliability information to the fourth reliability information are repeated a predetermined number of times, It is possible to determine the number of active base stations and the pair of connections between the user terminals.

As described above, each of the base stations 110, 120, and 130 determines the base station in the active state based on the sum of the first reliability information and the third reliability information, the sum of the fifth reliability information and the sixth reliability information, May be determined to be a value less than a preset number so as to minimize energy consumption of the entire wireless communication system.

For example, in FIG. 1, the first BS 110, the second BS 120, and the third BS 130 may transmit data to the second BS 120 and the third BS 130 based on the fifth reliability information and the sixth reliability information. 3 base station 130 is in an active state (shaded in FIG. 1). The first base station 110, the second base station 120 and the third base station 130 are connected to each other by a connection between the second base station 120 and the first user terminal 140 based on the first reliability information and the third reliability information, The connection between the second base station 120 and the second user terminal 150 and the connection between the third base station 130 and the third user terminal 160 and the connection between the third base station 130 and the fourth user terminal 170 It can be determined that activating the connection is optimal.

Each of the base stations 110, 120, and 130 and the user terminals 140, 150, 160, and 170 may repeatedly generate and exchange the first to sixth reliability information according to a predetermined cycle. As the period is shorter, the amount of calculation in each of the base stations 110, 120, and 130 and the user terminals 140, 150, 160, and 170 increases, but energy consumption of the wireless communication system can be minimized. In addition, the generation of the first to sixth reliability information and the mutual exchange of the first to sixth reliability information can be repeated until the number of active base stations having a minimum energy consumption and the user terminal connected thereto are determined.

Wherein the first reliability information, the second reliability information, the third reliability information, the fourth reliability information, the fifth reliability information, the sixth reliability information, and the seventh reliability information are expressed by the following mathematical formulas 1, (2), (3), (4), (5), (6) and (7).

이고,

는 i-기지국과 연결 가능한 사용자 단말 후보군에 속하는 사용자 단말 b로부터 수신되는 메시지들 중에서 l번째로 큰 값을 의미한다.)(here,

ego,

Is the l-th largest value among the messages received from the user terminal b belonging to the user terminal candidate group connectable to the i-th base station.

이고, a는 사용자 단말의 인덱스로서

이고,

는 기지국 i와 사용자 단말 a가 연결되었을 때 요구되는 송신 전력을 의미한다. 또한,

는 i번째 기지국들까지 중에서 활성화 상태의 기지국 수를 의미하고,

는 i 번째 기지국과 상기 i번? 기지국에 연결된 사용자 단말들 간의 에너지 소모량을 의미한다.

는 i번째 기지국에 연결된 사용자 단말의 수를 의미한다.Here, i is an index of a base station

, A is the index of the user terminal

ego,

Denotes the transmission power required when the base station i and the user terminal a are connected. Also,

Denotes the number of base stations in the active state among the i-th base stations,

And the i < th > And energy consumption between user terminals connected to the base station.

Denotes the number of user terminals connected to the i < th > base station.

는

이다.here,

The

to be.

As can be seen from Equations 1 to 7, the first reliability information, the second reliability information, the third reliability information, the fourth reliability information, the fifth reliability information, the sixth reliability information And the seventh reliability information are related to each other and each of the base stations 110, 120 and 130 and each of the user terminals 140, 150, 160 and 170 repeatedly transmits the first reliability information, the second reliability information, the third reliability information, , Exchange the fifth reliability information, the sixth reliability information, and the seventh reliability information, and update the information again based on the exchanged information.

Meanwhile, in another example, each of the base stations 110, 120, and 130 and each of the user terminals 140, 150, 160, and 170 may use the lookup table to determine the first reliability information, the second reliability information, Reliability information, the fifth reliability information, the sixth reliability information, and the seventh reliability information. The lookup table sets some of the elements included in each reliability information or each reliability information as variables, and the reliability information corrected for each of the variables and the values that can be considered for each variable in the form of a table It can be said that it was created.

2 is a conceptual diagram illustrating a state in which a plurality of base stations and a user terminal exchange reliability information through functionally defined virtual nodes according to an embodiment of the present invention. 2 is a conceptual diagram schematically illustrating the relationship between the base stations 110, 120, and 130 intertwined in the network and the user terminals 140, 150, 160, and 170. The node illustrated in FIG. 2 includes a plurality of base stations, It can be called a factor node (variable node) that defines the necessary conditions and variables to determine the connection relationship.

Specifically, the first base station 110 includes the conditional virtual nodes 111 and 112 and the variable virtual node 113, and the second base station 120 includes the conditional virtual nodes 121 and 122 and the variable virtual node 123 And the third base station 130 includes the conditional virtual nodes 131 and 132 and the variable virtual node 133. [ The first user terminal 140 includes conditional virtual nodes 141, 142, 143 and 144 and variable virtual nodes 145 and 146 and 147. The second user terminal 150 includes conditional virtual nodes 151 162, 163, 164 and variable virtual nodes 165, 166, 163, 164 and 154, and variable virtual nodes 155, 156 and 157, , 167 and a fourth user terminal 170 may include conditional virtual nodes 171, 172, 173, 174 and variable virtual nodes 175, 176, The variable virtual node 201 may be included between the conditional virtual nodes 112 and 122 and the variable virtual node 202 may be included between the conditional virtual nodes 122 and 132. [

는 i-기지국에 연결된 사용자 단말의 수 및 그 때 요구되는 추가 송신전력에 관한 조건으로서, 아래의 수학식 8로 표현될 수 있다.The conditional virtual nodes 111, 121, and 131

Can be expressed by the following equation (8) as a condition concerning the number of user terminals connected to the i-base station and the additional transmission power required at that time.

로 정의되고,

는 i-기지국과 a-사용자 단말이 연결되었는지를 나타내는 이진값으로서, i-기지국과 a-사용자 단말이 연결된 경우 1값을 나타내고, 연결되지 않은 경우에는 0값을 나타낸다. 또한,

는 은 i-기지국과 연결 가능한 사용자 단말 후보군을 의미한다. 따라서, 상기 수학식 8은 i-기지국과 a-사용자 단말이 연결되었는지를 나타내는 정보인

의 합과 i-기지국에 연결된 사용자 단말의 수를 나타내는

가 일치하는 경우에는 그때 필요한 송신전력 값을 산출하고, 그 이외의 경우에는 무한대의 결과를 산출한다.here,

Lt; / RTI >

Is a binary value indicating whether the i-base station and the a-user terminal are connected, and indicates a value of 1 when the i-base station and the a-user terminal are connected. Also,

Denotes a user terminal candidate group connectable to an i-th base station. Therefore, Equation (8) is information indicating whether the i-base station and the a-user terminal are connected

And the number of user terminals connected to the i-th base station

The transmission power value required at that time is calculated, and in the other cases, a result of infinity is calculated.

은 i-기지국까지의 활성화된 기지국의 수의 제한조건에 관한 것으로서, 아래의 수학식 9로 표현될 수 있다.The conditional virtual nodes 112, 122, 132

Is related to the limitation of the number of activated base stations to the i-th base station, and can be expressed by the following equation (9).

로 정의되고,

는 []내부의 조건을 만족할 때 1 값을 산출하는 함수이다. 따라서, 상기 수학식 9는 (i-1)번째 기지국까지의 활성 상태의 기지국에 1을 더한 수가 i번째 기지국까지의 활성 상태의 기지국 수와 같은 경우에는 0값을 산출하고, 그 이외의 경우에는 무한대의 결과를 산출한다.here,

Lt; / RTI >

Is a function that calculates a value of 1 when the condition inside [] is satisfied. In Equation (9), a value of 0 is calculated when the number of 1s added to the base station active to the (i-1) th base station is equal to the number of base stations active to the i-th base station, Yields infinite results.

는 하나의 사용자 단말이 하나의 기지국과 연결되어야 하는 조건으로서, 아래의 수학식 10으로 표현될 수 있다.The conditional virtual nodes 144, 154,

Is a condition that one user terminal must be connected to one base station, and can be expressed by the following Equation (10).

로 정의되고,

는 사용자 단말 a가 연결 가능한 기지국 후보군을 의미한다. 따라서, 상기 수학식 10은 사용자 단말 a에 대하여 i-기지국과 a-사용자 단말이 연결되었는지를 나타내는 정보인

의 합이 1인 경우에만 0값을 산출하고, 그 이외의 경우에는 무한대의 결과를 산출한다.here,

Lt; / RTI >

Denotes a base station candidate group to which a user terminal a can connect. Therefore, Equation (10) represents information indicating whether the i-base station and the a-user terminal are connected to the user terminal a

0 " is calculated only when the sum of " 1 " is " 1 ", and in other cases, the result is infinite.

는 i-기지국과 a-사용자 단말의 연결되었을 때 필요한 송신전력에 관한 조건을 의미한다.The conditional virtual nodes 141, 142, 143, 151, 152, 153, 161, 162, 163, 171, 172,

Denotes a condition related to the transmission power required when the i-base station and the a-user terminal are connected.

As described above, the first reliability information, the second reliability information, the third reliability information, the fourth reliability information, and the third reliability information described above with reference to FIG. 1 by the virtual nodes associated with the base stations 110, 120, and 130 and the user terminals 140, Information, fifth reliability information, and sixth reliability information may be generated and exchanged. For example, the variable virtual nodes 145, 146, 147, 155, 156, 157, 165, 166, 167, 175, 176, Information about the transmission power and channel information between each of the base stations and the user terminal received from the base station and the conditional virtual nodes 144, 154, and 164 received from the base stations, 162, 163, 171, 172, (Seventh reliability information) related to the probability of being connected to the conditional virtual nodes 111, 121, and 131, and transmits the first reliability information to the conditional virtual nodes 111, 121, The conditional virtual nodes 111, 121 and 131 transmit the third reliability information to the variable virtual nodes 145, 146, 147, 155, 156, 157, 165, 166, 167, 175, 176 and 177 . The conditional virtual nodes 112, 122, and 132 and the variable virtual nodes 201, 202, and 203 exchange the second reliability information and the fourth reliability information related to the number of active base stations among the plurality of base stations . The conditional virtual nodes 112, 122, and 132 and the variable virtual nodes 113, 123, and 133 are configured to transmit the fifth reliability information and the sixth reliability information related to the number of user terminals connected to each base station, Information can be exchanged.

In this way, the virtual node associated with each of the base stations 110, 120, and 130 and the user terminals 140, 150, 160, and 170 can exchange the first through seventh reliability information, The base station and the user terminal connected to the base station can be determined.

As a result, if any one of the conditions described above through Equations (8) to (10) is not satisfied, the result of Equation (11) becomes a negative infinity value, It is possible to determine the base station in the active state and the user terminal connected thereto when the result values of Equations (8) to (10) become the minimum finite values.

3 is a flowchart illustrating a method of controlling a base station in a wireless communication system according to an embodiment of the present invention. The base station control method illustrated in FIG. 3 may be performed by the base station and the user terminal described above with reference to FIG. Therefore, even if omitted below, the description of the base station and the user terminal through FIG. 1 may be applied to FIG.

In step S310, each base station and each user terminal can set an initial value of reliability information including first reliability information and third reliability information. For example, the initial value of each reliability information may be zero.

In step S320, each base station may receive first reliability information from neighboring user terminals related to transmit power between each base station and at least one user terminal. In step S330, each base station can receive second reliability information related to the number of active base stations among the plurality of base stations from neighboring base stations.

Further, in step S340, each base station determines whether or not the additional transmission power required by increasing the number of user terminals connected to each base station based on the first reliability information received in step S310 and the second reliability information received in step S320 It is possible to generate the related third reliability information. In addition, each base station can transmit the third reliability information generated by itself to neighboring user terminals. In addition, the user terminal receives the third reliability information from an adjacent base station and updates the first reliability information based on the third reliability information.

In step S350, each base station can generate fourth reliability information related to the required additional transmission power by increasing the number of active base stations and the number of user terminals connected to each base station among a plurality of base stations. In addition, each base station may exchange the fourth reliability information with neighboring other base stations.

In step S360, each base station can generate fifth reliability information indicating the active state preference of each base station based on the second reliability information received in step S330 and the fourth reliability information generated and received in step S350 . Also, in step S360, each base station can generate sixth reliability information related to the additional transmission power required by increasing the number of user terminals connected to each base station and the first reliability information received in step S310.

These steps S310 to S360 may be repeated a predetermined number of times in accordance with a predetermined period. For example, the steps S310 to S360 may be repeated until the resultant value of at least some of the first to sixth reliability information converges to a predetermined value.

In step S370, after steps S310 to S360 are repeatedly performed a predetermined number of times, each base station determines a base station operating in an active state among a plurality of base stations based on the fifth reliability information and the sixth reliability information , The active connection relationship between the active base station and each user terminal can be determined. In addition, the base station determined to be in the inactive state may transmit a handover command to establish a connection with the base station determined to be active for the user terminal connected to the base station.

As described above, according to an embodiment of the present invention, each base station and each user terminal repeatedly exchange reliability information (reliability messages) a predetermined number of times without a central controller or a control device, Can be minimized in a distributed activation state. The present invention can reduce the energy of the network by, for example, deactivating the operation of some of the base stations in an off-peak time when excessive radio traffic is not required.

4 is a flowchart illustrating a method of controlling a base station in a wireless communication system according to another embodiment of the present invention. The base station control method shown in FIG. 4 can be performed by the base station and the user terminal described above with reference to FIG. Therefore, the contents described with respect to the base station and the user terminal through FIG. 1 may be applied to FIG. 4 even if omitted below.

In step S410, each base station may generate and repeatedly update the fifth reliability information and the sixth reliability information as described above with reference to Figs. 1 to 3 above. In addition, in step S420, each base station may calculate the sum of the fifth reliability information and the sixth reliability information generated in step S410.

In step S430, each base station may determine to activate a base station whose sum of the fifth reliability information and the sixth reliability information has a value greater than zero. In addition, in step S440, each base station calculates the sum of the first reliability information and the third reliability information received and updated as described with reference to Figs. 1 to 3 above. The first reliability information and the third reliability information are generated for a one-to-one connection relationship between each base station and each adjacent user terminal of each base station, The first reliability information and the third reliability information may be calculated for a one-to-one connection relationship between the first reliability information and the third reliability information.

In step S450, each base station may determine to activate a connection between the base station and the user terminal, the sum of the first reliability information and the third reliability information being greater than zero.

The first to sixth reliability information may be calculated as a probability value having a value between 0 and 1, and as described above with reference to FIG. 2, a request is made between each base station and each user terminal in the wireless communication system If the condition is not satisfied, it indicates an infinite value. Therefore, in step S430 and step S450, it is possible to activate the connection state between the base station and the base station and the user terminal in the case of having a finite value larger than 0 but not infinite.

5 is a flowchart illustrating a method of controlling a base station in a wireless communication system according to another embodiment of the present invention. The base station control method shown in FIG. 5 can be performed by the base station and the user terminal described above with reference to FIG. Therefore, although omitted in the following description, the description of the base station and the user terminal in FIG. 1 may also be applied to FIG. 5, a wireless communication system including two base stations 510 and 520 and two user terminals 530 and 540 will be described. It is also assumed that the base station closest to the first user terminal 530 is the first base station 510 and the base station closest to the second user terminal 540 is the second base station 520. [

In step S501, the base stations 510 and 520 may transmit information including a reference signal to neighboring user terminals 530 and 540. [ For example, the first base station 510 periodically broadcasts a reference signal to the first user terminal 530 and the second user terminal 540, and the second base station 520 broadcasts a reference signal periodically to the second user terminal 540. [ (broadcast). In step S502, the user terminals 530 and 540 measure the signal quality based on the information received in step S501, and generally determine the base station that is closest to the base station and transmit a connection request signal. For example, the first user terminal 530 may transmit a connection request signal to the first base station 510 and the second user terminal 540 may transmit a connection request signal to the second base station 520. In step S503, the first base station 510 transmits a connection permission command to the first user terminal 530, thereby establishing a communication connection between the first user terminal 530 and the first base station 510. [ In addition, the second base station 520 transmits a connection permission command to the second user terminal 540, thereby establishing a communication connection between the second user terminal 540 and the second base station 520. In step S504, the user terminals 530 and 540 may report the quality of the reference signal received from the adjacent base station to the connected base station. For example, the first user terminal 530 reports the reference signal quality of the first base station 510 to the first base station 510, the second user terminal 540 reports the reference signal quality of the first base station 510, Quality and the reference signal quality of the second base station 520 to the second base station 520. [ For example, the user terminals 530 and 540 may report the quality of the reference signal in the form of a reference signal received power (RSRP) value.

In step S505, each of the base stations 510 and 520 acquires information on the user terminal associated with itself, channel information on its own communication connection with the user terminal, signal quality information, and the like, received previously through step S504, 3 to generate and exchange the first to sixth reliability information. According to an embodiment of the present invention, since each of the base stations 510 and 520 already knows the information of the user terminal associated with itself, the channel information of its communication connection with the user terminal, and the signal quality information, It is possible to directly generate the first reliability information and directly generate other reliability information based on the generated first reliability information. Also, in step S505, after the reliability information is updated and exchanged a predetermined number of times, the connection between the active base station and the base station and the user terminal is determined.

In step S506, the base station (e.g., the second base station 520) determined to be inactive is informed to the user terminal (e.g., the second user terminal 540) (E.g., handover command transmission). In addition, in step S507, the second user terminal 540 may instruct the mobile terminal to move the communication connection to the first base station 510 And may transmit a connection request signal to the first base station 510 according to the handover command received in step S506. In step S508, the first base station 510 transmits a connection permission command to the second user terminal 540 so that a communication connection can be established between the second user terminal 540 and the first base station 510 .

In this way, the second user terminal 540 is closest to the second base station 520 and is connected to the second base station 520. However, energy consumption of the entire wireless communication system can be reduced through exchange of reliability information between the base stations The second base station 520 may be turned off and the second user terminal 540 may be connected to the first base station 510. [

Thereafter, the first user terminal 530 and the second user terminal 540 are connected to the first base station 510 for a predetermined period of time, the communication state is maintained, and steps S501 to S508 Can be repeatedly performed.

6 is a block diagram illustrating a base station apparatus according to an embodiment of the present invention. As shown in FIG. 6, the base station apparatus 600 according to an embodiment of the present invention may include a communication unit 610 and a processor 620. However, the base station apparatus 600 may further include another configuration not shown in FIG. 6 in addition to the communication unit 610 and the processor 620. For example, the base station apparatus 600 may include a storage unit operatively associated with the communication unit 610 and the processor 620. The storage unit may store the above-described lookup table, and the processor 620 may utilize the lookup table stored in the storage unit to generate or update reliability information.

The first to sixth reliability information referred to in FIG. 6 has been described in detail with reference to FIGS. 1 and 2, and a detailed description thereof will be omitted. The base station apparatus 600 shown in FIG. 6 may be the same as each of the base stations 110, 120, and 130 included in the wireless communication system 10 described above with reference to FIGS.

The communication unit 610 can receive the first reliability information from the adjacent user terminal 630 of the base station apparatus 600. [ The communication unit 610 may exchange the second reliability information and the fourth reliability information with another neighboring base station apparatus 640 of the base station apparatus 600. [ In addition, the communication unit 610 can transmit the third reliability information to the adjacent user terminal 630. [ The communication unit 610 may transmit and receive reliability information via one or more of wireless or wireline communication. In addition, the communication unit 610 can transmit a command or a signal necessary for a communication connection, such as a handover command, to an adjacent user terminal according to the determination of the processor 620. [

The processor 620 can generate third reliability information related to the required additional transmission power by increasing the number of user terminals connected to the base station apparatus 600 based on the first reliability information and the second reliability information received by the communication section have. The processor 620 also generates fourth reliability information related to the required additional transmit power by increasing the number of active stations in the plurality of base stations throughout the wireless communication system and the number of user terminals connected to the base station device 600 can do.

The processor 620 may generate the fifth reliability information indicating the active state preference of the base station apparatus 600 based on the second reliability information and the fourth reliability information received by the communication unit 610. [ In addition, the processor 620 may generate sixth reliability information related to the first reliability information received by the communication unit 610 and the additional transmission power required by increasing the number of user terminals connected to the base station apparatus 600 .

In addition, the processor 620 can determine whether the base station apparatus 600 is active based on the fifth reliability information and the sixth reliability information. For example, the processor 620 may calculate the sum of the fifth reliability information and the sixth reliability information, and may determine to operate in an active state if the result has a value greater than zero.

In addition, the processor 620 calculates the sum of the first reliability information and the third reliability information with respect to the connection relationship of at least one user terminal connected to the base station apparatus 600, and when the result is greater than 0 It may decide to activate the connection between the base station 600 and the corresponding user terminal.

The above-described base station control method may also be implemented in the form of a recording medium including instructions executable by a computer such as a program module executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, the computer-readable medium can include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes any information delivery media, including computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transport mechanism.

The above-described base station control method may also be implemented in the form of a computer program stored in a recording medium.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

110, 120, 130, 510, 520:
140, 150, 160, 170, 530, 540:
600: base station device
610:
620: Processor
630: peripheral user terminal
640: peripheral base station device

Claims (21)

A base station control method of a wireless communication system including a plurality of base stations,
(a) receiving each of the plurality of base stations from a neighboring user terminal of each base station with first reliability information related to transmission power between the respective base station and at least one user terminal;
(b) receiving, by the respective base stations, second reliability information related to the number of active base stations among the plurality of base stations from another adjacent base station of each base station;
(c) generating third reliability information related to the additional transmit power required by each base station by increasing the number of user terminals connected to the respective base station based on the first reliability information and the second reliability information ; And
(d) each of the base stations transmitting the third reliability information to neighboring user terminals of the respective base stations,
/ RTI > The method according to claim 1,
Wherein the first reliability information, the second reliability information, and the third reliability information have a value between 0 and 1, and increase as the preference for connection between each base station and the user terminal increases. . 3. The method of claim 2,
Wherein the first reliability information and the third reliability information are generated for a one-to-one connection relationship between each base station and each adjacent user terminal of each base station. The method according to claim 1,
(e) generating fourth reliability information related to the additional transmit power required by each base station as the number of active base stations of the plurality of base stations and the number of user terminals connected to each base station increases; And
(f) exchanging the fourth reliability information with neighboring base stations of the respective base stations,
Further comprising the steps of: 5. The method of claim 4,
(g) generating fifth reliability information indicating the active state preference of each base station based on the second reliability information and the fourth reliability information;
(h) generating sixth reliability information related to the additional transmission power required by each base station as the first reliability information and the number of user terminals connected to the respective base station are increased; And
(i) determining, by the base station, a base station operating in an active state among the base stations based on the fifth reliability information and the sixth reliability information,
Further comprising the steps of: 6. The method of claim 5,
The step (i)
(i1) calculating a sum of the fifth reliability information and the sixth reliability information; And
(i2) determining to activate a base station whose sum of the fifth reliability information and the sixth reliability information is greater than zero,
The base station comprising: 6. The method of claim 5,
Wherein the steps (a), (b), (c), (d), (g) and (h) are repeatedly performed. 6. The method of claim 5,
(j) calculating a sum of the first reliability information and the third reliability information for a one-to-one connection relationship between each base station and each neighboring user terminal of each base station; And
(k) determining that each of the base stations activates a connection between a base station and a user terminal, the sum of the first reliability information and the third reliability information being greater than zero,
Further comprising the steps of: 9. The method of claim 8,
Wherein the step (g), the step (h), and the step (i) are the same as the steps (a), (b), wherein step (d), (e) and (f) are repeated after a predetermined number of iterations. 9. The method of claim 8,
Wherein the number of base stations in the activated state equal to or less than a predetermined number is determined based on the determination result in the step (i) and the step (k). The method according to claim 1,
Wherein the first reliability information is based on transmission power and channel information between each base station and each user terminal and seventh reliability information related to a probability that each user terminal is connected to any one of the plurality of base stations, Wherein the base station is generated by the terminal. The method according to claim 1,
Wherein the first reliability information, the second reliability information and the third reliability information are information related to transmit power additionally consumed according to the number of user terminals connected to each of the plurality of base stations. The method according to claim 1,
Before the step (a)
Each of the base stations establishing an initial value of the first reliability information and the third reliability information,
Further comprising the steps of: 6. The method of claim 5,
At least one of the first reliability information, the second reliability information, the third reliability information, the fourth reliability information, the fifth reliability information, and the sixth reliability information is transmitted to each of the plurality of base stations or the user terminal Wherein the virtual node is generated by an associated virtual node. In the base station apparatus,
A communication unit, and a processor,
The processor comprising:
As the number of user terminals connected to the base station device increases based on the first reliability information related to the transmission power between the base station device and the at least one user terminal and the second reliability information related to the number of base stations active among the plurality of base stations Generating third reliability information related to the required additional transmit power,
Wherein,
Receiving the first reliability information from an adjacent user terminal of the base station apparatus;
Receiving the second reliability information from another neighboring base station of the base station apparatus; And
Transmitting the third reliability information to an adjacent user terminal of the base station apparatus,
To the base station apparatus. 16. The method of claim 15,
Wherein the first reliability information, the second reliability information, and the third reliability information have a value between 0 and 1, and increase as the preference for connection between each base station and the user terminal increases. 16. The method of claim 15,
The processor comprising:
Further comprising the step of generating fourth reliability information related to the required additional transmission power by increasing the number of active base stations of the plurality of base stations and the number of user terminals connected to the base station device,
Wherein,
And exchanging the fourth reliability information with an adjacent base station of the base station apparatus. 18. The method of claim 17,
The processor comprising:
Generating fifth reliability information indicating an active state preference of the base station apparatus based on the second reliability information and the fourth reliability information;
Generating sixth reliability information related to the required additional transmit power by increasing the number of user terminals connected to the base station apparatus; And
Determining whether the base station apparatus is active based on the fifth reliability information and the sixth reliability information,
To the base station apparatus. 19. The method of claim 18,
The processor comprising:
Calculating a sum of the first reliability information and the third reliability information for a one-to-one connection relationship between the base station device and each adjacent user terminal of the base station device; And
Determining to activate the connection between the base station and the user terminal if the sum of the first reliability information and the third reliability information is greater than zero,
To the base station apparatus. A wireless communication system comprising a plurality of base station apparatuses according to any one of claims 15 to 19. A computer-readable recording medium storing a program for causing a computer to execute the method according to any one of claims 1 to 14.

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