JP2015070613A - Method and device for selecting cell performing intermittent transmission from among a plurality of cells - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for appropriately selecting at least one cell from among a plurality of cells, that can reduce interference between small cells and that can avoid greatly affecting performance of the whole communication system.SOLUTION: A method includes the steps of: acquiring at least one of interference information on each cell of a plurality of cells, a quantity of users of a predetermined type of each cell, and an intermittent transmission history frequency of each cell, the interference information of each cell indicating an interference degree of the cell to the other cell of the plurality of cells; and selecting at least one cell that performs intermittent transmission from among the plurality of cells on the basis of at least one of the interference information of each cell, the quantity of users of the predetermined type, and the intermittent transmission history frequency.

Description

  The present invention relates to a technique for reducing interference between cells, and more specifically to a method and a device for selecting a cell for intermittent transmission from a plurality of cells.

  In a mobile communication network, a plurality of macro cells (or macro base stations) are arranged to provide services to mobile users. However, in an area where users are concentrated, such as a gymnasium or a shopping center, a macro cell alone cannot provide sufficient network capacity and provide a service suitable for the user. Therefore, in addition to the macro cell, a plurality of small cells, such as a micro cell, a pico cell, and the like, which are cells having lower transmission power and / or smaller coverage than the macro cell in such an area. It is densely arranged and provides services to users through macro cells and these small cells.

  However, interference may occur between a plurality of small cells arranged densely, and the interference between the small cells increases as the density of the small cells arranged increases. In order to solve this problem, a method has been proposed in which the small cells are intermittently transmitted to reduce interference between the small cells. In a conventional method, for each transmission interval, one small cell with the lowest current work load is muted, that is, the small cell is not allowed to transmit data at this transmission interval. By reducing the interference received by other small cells (especially edge users) and increasing the throughput of users of other small cells, the performance of these users is improved. On the other hand, a user of a small cell (especially a central user) selected to perform intermittent transmission at a certain transmission interval cannot transmit data at the transmission interval. User throughput is reduced and the performance of these users is reduced. In many cases, the performance gain brought to the user of another small cell by intermittent transmission of the small cell selected by the above method cannot often compensate for the performance degradation of the user of the small cell itself. Reduce the performance of the communication system.

  Therefore, when arranging a plurality of small cells, for each transmission interval, appropriately select a small cell that performs intermittent transmission from the plurality of small cells, to reduce interference between the small cells, at the same time There is a need for new methods and devices that can prevent significant adverse effects on communication system performance.

  In view of the above problems, the present invention has been achieved. One object of the present invention is a method and a device for selecting a cell for intermittent transmission from a plurality of cells, wherein the method and device are used for each transmission interval from among the plurality of cells. By providing a method and a device capable of appropriately selecting at least one cell and performing intermittent transmission, thereby reducing interference between small cells and preventing a significant adverse effect on the performance of the entire communication system at the same time. is there.

  According to an aspect of the present invention, there is provided a method for selecting a cell for intermittent transmission from a plurality of cells, the interference information of each cell in the plurality of cells, and a predetermined type of each cell. Obtaining at least one of the number of users and the intermittent transmission history frequency of each cell; however, the interference information of each cell indicates the degree of interference of the cell with other cells in the plurality of cells. And selecting a cell that performs at least one intermittent transmission from among the plurality of cells based on at least one of interference information of each cell, the number of users of a predetermined type, and intermittent transmission history frequency; A method comprising:

  According to another aspect of the present invention, there is provided a device for selecting a cell for intermittent transmission from a plurality of cells, the interference information of each cell in the plurality of cells, the predetermined information for each cell. An information acquisition device that acquires at least one of the number of types of users and the intermittent transmission history frequency of each cell; however, the interference information of each cell indicates that the cell is another cell in the plurality of cells A cell for performing at least one intermittent transmission from among the plurality of cells based on at least one of the interference information of each cell, the number of users of a predetermined type, and the intermittent transmission history frequency And a cell selection device.

  Using the method and device according to the above aspect of the present invention, for each transmission interval, the degree of interference of each cell with other cells, the number of users of a given type (eg, central user) in each cell, and the respective A cell that performs intermittent transmission can be selected based on at least one of the intermittent transmission history frequencies of the cell (for example, the number or time of intermittent transmission performed within a predetermined time period in the past). The degree of interference of each cell with respect to other cells can reflect the performance gain of users of other cells when the cell is muted in the transmission interval, and the number of users of a given type in the cell depends on the transmission interval. Since the performance loss of a predetermined type of user of the cell when the cell is muted can be reflected, the cell selected based on these pieces of information makes the performance gain as large as possible and the performance loss as small as possible, thereby enabling communication. By improving the overall system performance and at the same time preventing any or several cells from being selected to perform intermittent transmissions too frequently, their performance is prevented from deteriorating significantly.

The above and other objects, features and advantages of the present invention will become more apparent by describing in detail the embodiments of the present invention with reference to the drawings. In the drawings, the same reference numeral indicates the same element throughout.
1 illustrates an exemplary communication system to which embodiments of the present invention can be applied. It is a flowchart which shows the method of selecting the cell which performs intermittent transmission from the some cell by 1st Example of this invention. FIG. 3 is a flow diagram illustrating one exemplary method for performing step S202 shown in FIG. FIG. 4 illustrates an example of a process for selecting at least one small cell from six small cells by the method illustrated in FIG. 3. It is a block diagram which shows the device which selects the cell which performs intermittent transmission from the some cell by the 1st Example of this invention. It is a flowchart which shows the method of selecting the cell which performs intermittent transmission from the some cell by the 2nd Example of this invention. It is a block diagram which shows the device which selects the cell which performs intermittent transmission from the some cell by the 2nd Example of this invention. It is a flowchart which shows the method of selecting the cell which performs intermittent transmission from the some cell by the 3rd Example of this invention. It is a block diagram which shows the device which selects the cell which performs intermittent transmission from the some cell by the 3rd Example of this invention. It is a flowchart which shows the method of selecting the cell which performs intermittent transmission from the some cell by the 4th Example of this invention. It is a block diagram which shows the device which selects the cell which performs intermittent transmission from the some cell by the 4th Example of this invention.

  Hereinafter, a method and a device for selecting a cell for intermittent transmission from a plurality of cells according to an embodiment of the present invention will be described with reference to the drawings. The cell may be the above-described small cell such as a micro cell or a pico cell, or may be another type of cell other than the small cell such as a macro cell. In the following, embodiments of the present invention will be described by taking a small cell as an example, but the description can be applied to other types of cells.

  First, an exemplary communication system to which embodiments of the present invention can be applied will be described with reference to FIG. The exemplary communication system may be, for example, an LTE (Long Term Revolution) communication system or an LTE-Advanced communication system, in which the access network employs a centralized radio access network (C-RAN) configuration. May be. As shown in FIG. 1, in a C-RAN configuration, a centralized base station eNodeB is connected to an evolved packet core (EPC) network and a plurality of baseband unit (BBU) pools and a plurality of BBU pools connected to the BBU pool. Each of the plurality of RREs is controlled by a corresponding BBU in the BBU pool and is arranged at different positions to form a plurality of small cells. Each small cell may have one or more users (ie, “user equipment UE”). In FIG. 1, for convenience of illustration, three BBU1-3 and three RRE1-3 are shown, and these three RREs form three small cells 1-3, and each small cell has its own one. Have a user. However, for example, UE1 is a central user of small cell 1, and UE2 is an edge user of small cell 1. As shown above, interference may occur between the small cells 1-3. As shown in FIG. 1, the edge user UE <b> 2 of the small cell 1 receives interference from the small cell 2. It should be understood that the quantities of RRE, BBU and UE shown in FIG. 1 are exemplary, and other quantities of RRE, BBU and UE may exist.

  In the exemplary communication system shown in FIG. 1, at least one small cell is selected from the plurality of small cells using the method and device according to the embodiments of the present invention for each transmission interval, and By mute, interference with other small cells of the small cell can be removed.

  In brief, a method for selecting a small cell that performs intermittent transmission from among a plurality of small cells according to an embodiment of the present invention includes: interference information of each small cell in the plurality of small cells; Obtaining at least one of the number of users of a predetermined type of cell and the intermittent transmission history frequency of each small cell, provided that the interference information of each small cell indicates that the small cell is a plurality of small cells. The degree of interference with other cells in the medium, and based on at least one of the interference information of each small cell, the number of users of a predetermined type and the intermittent transmission history frequency, at least one of the plurality of small cells Selecting a small cell for intermittent transmission. A device for selecting a small cell that performs intermittent transmission from among a plurality of small cells according to an embodiment of the present invention includes: interference information of each small cell in the plurality of small cells; a predetermined type of each small cell; An information acquisition device that acquires at least one of the number of users and the intermittent transmission history frequency of each of the small cells, except that interference information of each small cell is different from that of the plurality of small cells. And at least one intermittent transmission among the plurality of small cells based on at least one of the interference information of each small cell, the quantity of predetermined types of users, and the intermittent transmission history frequency. And a cell selection device that selects a small cell to be performed.

  The invention will now be described with reference to specific embodiments of the invention.

(First embodiment)
Hereinafter, a flowchart of a method for selecting a small cell for intermittent transmission from a plurality of small cells according to the first embodiment of the present invention will be described with reference to FIG. The method may be performed in the eNodeB shown in FIG. For example, the method may be executed by installing a small cell controller operably coupled to the BBU pool in the eNodeB shown in FIG.

  As shown in FIG. 2, in step S201, interference information of each small cell in the plurality of small cells is acquired. However, the interference information of each small cell indicates the degree of interference of the small cell with respect to other small cells among the plurality of small cells.

  In this embodiment, for each small cell, the other small cells of the small cell using the number of small cells (ie, “damaged cells”) that receive interference of the small cell among the plurality of small cells. The degree of interference with respect to may be indicated. As the number of damaged cells of the small cell increases, the degree of interference of the small cell with other small cells increases. Conversely, as the number of damaged cells of the small cell decreases, the degree of interference of the small cells with other small cells decreases. In this case, the interference information of each small cell may be a value indicating the number of damaged cells of the small cell.

  You may determine the quantity of the damage cell of each small cell by the quality measurement report received from the user of each small cell. For example, in the example shown in FIG. 1, for the small cell 1, the number of damaged cells in the small cell 1 is determined based on the reception quality measurement reports received from users of all other small cells (that is, the small cells 2 and 3). Also good. Specifically, each user of the small cell 2 measures the reference signal received power (RSRP) of the serving cell (that is, the small cell 2) and the RSRP of the small cell 1, and the reception quality measurement report. To the base station. In the base station, for example, the difference between the two RSRPs may be calculated in the BBU 2 corresponding to the small cell 2 or in the small cell controller, and it may be determined whether or not the difference exceeds a predetermined threshold value. However, the threshold value may be appropriately set based on the necessity of design and / or the actual situation of the mobile communication network, and may be set to 6 dB, for example. When the difference is smaller than the threshold value, it may be considered that the small cell 1 is causing interference to the small cell 2, that is, the small cell 2 is a damaged cell of the small cell 1. Conversely, when the difference is not smaller than the threshold value, it may be considered that the small cell 1 is not causing interference to the small cell 2, that is, the small cell 2 is not a damaged cell of the small cell 1. Similarly, each user of the small cell 3 measures the RSRP of the serving cell (that is, the small cell 3) and the RSRP of the small cell 1, and determines whether the small cell 3 is a damaged cell of the small cell 1 by the above method. May be. In this way, the number of damaged cells of the small cell 1 can be determined. For the small cell 2 as well, the number of damaged cells of the small cell 2 can be determined by executing the above process by the users of all other cells (that is, the small cells 1 and 3). For the small cell 3 as well, the number of damaged cells of the small cell 3 can be determined by executing the above process by the users of all other cells (that is, the small cells 1 and 2). It should be understood that the damaged cell is determined using RSRP as described above, but other parameters indicating reception quality (for example, Reference Signal Received Quality RSRQ: Signal to Interference Noise Ratio SINR: Signal to Interference) Plus Noise Ratio etc.) can determine the damaged cell in the same way.

  In step S202, based on the interference information of each small cell determined in step S201, a small cell that performs intermittent transmission is selected from the plurality of small cells.

  Specifically, one small cell having the largest interference information value may be selected as a small cell for intermittent transmission from the plurality of small cells. In this case, the number of damaged cells of each small cell may be simply compared, and the small cell having the largest number of damaged cells may be selected as a small cell that performs intermittent transmission.

  Alternatively, some small cells may be selected from among the plurality of small cells as small cells that perform intermittent transmission. The selection can be made by various methods. In the first exemplary method, the plurality of small cells may be arranged according to the number of damaged cells, and some small cells may be selected as small cells for intermittent transmission from the small cells with the largest number of damaged cells. . In the second exemplary method, intermittent transmission is performed on at least one small cell having the largest interference information value (ie, the number of damaged cells) among the plurality of small cells and satisfying a predetermined condition. You may select in order as a cell. Hereinafter, the second exemplary method for executing Step S202 will be described with reference to FIGS. 3 and 4. However, FIG. 3 shows a flow diagram of the second exemplary method, and FIG. 4 shows the process of selecting at least one small cell from six small cells using the second exemplary method. An example is shown.

  As shown in FIG. 3, a relationship diagram may be created for the plurality of small cells in step S301. The relationship diagram reflects the number of damaged cells of each small cell and the interference relationship between the small cells. In the example shown in FIG. 4, there are six small cells, that is, small cell # 1 to small cell # 6, and the number of these damaged cells is 2, 1, 2, 0, 1, and 3, respectively. In addition, the relationship diagram shown in FIG. 4A may be created for these six cells. In the relationship diagram, a circle indicates a corresponding small cell, a number in the circle indicates the number of damaged cells of the small cell, and an arrow between the two circles indicates an interference relationship between the two corresponding small cells. The circle at the rear of the arrow and the circle at the tip of the arrow correspond to a small cell that causes interference and a damaged cell of the small cell, respectively.

Next, in step S302, one small cell with the largest number of damaged cells is selected from the plurality of small cells as a small cell for intermittent transmission. In the example shown in FIG. 4, since the number of damaged cells of the small cell # 6 is the largest as shown by the gray circle in FIG. 4B, the small cell # 6 is selected as a small cell for intermittent transmission. Here, for convenience of explanation, the performance gain level that the small cell selected to perform the K-th intermittent transmission brings to other small cell users is denoted as G _k . As described above, the number of damaged cells of the small cell selected to perform intermittent transmission can reflect the level of performance gain brought to the users of other small cells, so G _k is selected k-th. You may set as the quantity _Nk of the damage cell of a small cell. In step S302, the small cell # 6 is a small cell of choice First, since that quantity N ₁ damage cell is 3, is a level G _{1 =} 3 performance gains Small cell # 6 results .

  In step S303, the relationship diagram is updated. Specifically, the circle corresponding to the small cell selected in step S301 and the arrow related to the circle (that is, the arrow toward the circle and the arrow leaving the circle) are deleted from the relationship diagram. In addition, since the small cell selected before that is muted, other small cells will not interfere with the small cell, and the number of damaged cells of other small cells may also change. In some cases, the number of damaged cells of other small cells may need to be updated, that is, the number of damaged cells of the small cell that causes interference to the small cell selected in step S302 is decreased by one. In the example shown in FIG. 4, the circle corresponding to the small cell # 6 and the arrow related to the circle are deleted from the relationship diagram shown in FIG. 4B, and the damage to the small cell # 3 that interferes with the small cell # 6. The number of cells is updated from “2” to “1”, and the relationship diagram shown in FIG. 4C is obtained.

Next, in step S304, the small cell with the largest number of damaged cells is selected from the remaining small cells, and it is determined whether or not it satisfies a predetermined condition. When the small cell with the largest number of selected damaged cells satisfies a predetermined condition, the small cell is determined as a small cell for intermittent transmission, and then the process returns to step S303, and step S303 and the subsequent steps are repeated. Conversely, if the selected small cell does not satisfy the predetermined condition, the small cell is selected and the intermittent transmission is stopped, that is, the selection operation is terminated. As an illustration of the predetermined condition, and performance gain level (G _K posed by small cell for the performance gain level posed by small cells (indicated as G K _{+ 1)} intermittent transmission is selected before one selected in step S304 (Shown) may satisfy G _{K + 1} > 0.5 * G _K. In this case, in the example shown in FIG. 4, the small cell with the largest number of damaged cells among the remaining small cells is the small cell # 1 (see FIG. 4C). And then determine whether it satisfies the predetermined condition. The performance gain level provided by the small cell # 1 is G ₂ = 2 and the performance gain level G ₁ = 3 provided by the previously selected small cell (small cell # 6 selected in step S302) is G _In order to satisfy ₂ > 0.5 * G ₁ , the small cell # 1 satisfies the predetermined condition, and therefore, as shown in a gray circle in FIG. 4D, the small cell # 1 performs intermittent transmission. Confirm as Thereafter, step S303 is executed again, that is, the relationship diagram shown in FIG. 4D is updated to the relationship diagram shown in FIG. 4E, and step S304 is executed again, that is, damage is caused in the remaining small cells. It is determined whether the small cell with the largest number of cells satisfies the predetermined condition. At this time, since the small cell having the largest number of damaged cells among the remaining small cells does not satisfy the predetermined condition, the selection process ends. As described above, the small cell # 6 and the small cell # 1 are finally selected as small cells for intermittent transmission by the above method.

It should be understood that in practice, the predetermined conditions described above may be any conditions appropriately set according to actual needs. For example, in addition to the above example of the predetermined condition, the predetermined condition is that the total number of the currently selected cell and the previously selected cell does not exceed a preset threshold value, or the predetermined condition is: S304 in selected performance gain level posed by small cell (G K _{+ 1} and shown) (indicated as G _K) performance gain levels brought about by small cell for intermittent transmission of the previously selected one is G _{K + 1>} 0.5 * G that _K was filled and performance gain level itself is selected the small cell leads is larger than a preset performance gain level threshold may be.

  It should also be noted that in the above selection process, if multiple small cells have the same number of damaged cells and the number is larger than the number of damaged cells of other small cells, these are randomly selected. Any one or more of these may be selected, or one or more of these may be selected according to additional criteria, eg, one or more of these may be selected according to the quantity of the central user Also good.

  The small cells other than the selected at least one small cell among the plurality of small cells may be set to perform normal transmission (that is, continuous transmission or non-intermittent transmission). Specifically, if another small cell is currently in the normal transmission state, the normal transmission is continued without changing the state, and if another small cell is currently in the intermittent transmission state, Normal transmission may be performed by changing the state to the normal transmission state.

  After selecting at least one small cell for intermittent transmission, information indicating the selected at least one small cell may be transmitted to a baseband unit corresponding to the at least one small cell in a base station. Various methods may be used to transmit the information. For example, information indicating the transmission state of each small cell is transmitted to each BBU in the BBU pool, and the transmission state instruction value corresponding to the small cell selected to perform intermittent transmission is set to the first value (for example, 1). ), The transmission state indication value corresponding to the small cell performing normal transmission is set to a second value (for example, 0), and the small cell corresponding to the transmission state indication value in the information received by each BBU Can determine whether or not to perform intermittent transmission. Alternatively, information indicating that the small cell corresponding to the BBU should perform intermittent transmission may be transmitted only to the BBU corresponding to the small cell selected to perform intermittent transmission. Similarly, information indicating that the transmission state of other small cells should be maintained or changed may be notified to the corresponding BBUs.

  Based on the received information, the BBU corresponding to the small cell selected to perform intermittent transmission instructs the cell to perform intermittent transmission, and the BBUs corresponding to other small cells perform normal transmission to these cells. You may instruct to do so.

  Using the above method, a small cell that performs at least one intermittent transmission can be selected from the plurality of small cells. Since the small cell that performs intermittent transmission is selected based on the degree of interference of the small cell with respect to other small cells, interference between these small cells can be performed by causing the selected small cell to perform intermittent transmission. Can be significantly reduced. As described above, by executing the above method at each transmission interval, an appropriate small cell can be selected for each transmission interval and intermittent transmission can be performed.

(Deformation)
In the first embodiment, for each small cell in the plurality of small cells, the degree of interference of the small cell with respect to other small cells is shown using the number of damaged cells of the small cell. . However, the degree of interference with other small cells of the small cell may be indicated by the number of edge users of the damaged cell of the small cell, and the small cell that performs intermittent transmission may be selected based on the number of edge users.

  Specifically, in this modification, in step S201 shown in FIG. 2, the number of edge users of the damaged cells of each small cell is acquired and used as interference information of the small cell. At this time, the interference of each small cell The information indicates the value of the quantity of edge users of the damaged cell of the small cell.

  The number of edge users of the damaged cells of each small cell may be determined based on the reception quality measurement report received from the users of each small cell. For example, in the example shown in FIG. 1, for the small cell 1, each user of all the damaged cells measures the RSRP of the serving cell and the RSRP of the small cell having the largest interference with it, and the measurement report is transmitted to the base station (specifically, Specifically, the data is transmitted to the corresponding BBU in the base station. In the base station, for example, in the BBU corresponding to the damaged cell, or in the small cell controller, a difference between the two RSRPs may be calculated to determine whether the difference exceeds a predetermined threshold. The threshold may be set appropriately based on design needs and / or the actual situation of the mobile communication network, and may typically be set to 6 dB. If the difference is less than the threshold, the user is an edge user of the victim cell, otherwise the user is a central user of the victim cell. In this way, the number of edge users of each damaged cell of the small cell 1 can be determined, and in addition, the number of central users of each damaged cell of the small cell 1 may be determined. Similarly, the number of edge users of each damaged cell of the small cell 2 and the small cell 3 may be determined, and in addition, the number of central users of each damaged cell of the small cell 2 and the small cell 3 may be determined. . In this way, the number of central users and edge users of each small cell can be determined. Similarly, the RSRP is merely an example, and the number of edge users of each small cell and the number of central users are similarly determined by other parameters (for example, reference signal reception quality RSRQ, signal-to-interference noise ratio SINR, etc.). The quantity can be confirmed. It should be noted that when a small cell has no damaged cell, the number of edge users of the damaged cell may be considered to be 0, and when the small cell has a plurality of damaged cells, the edge of the damaged cell The quantity of users may be the sum of the quantity of edge users of all damaged cells.

  Thereafter, in step S202 illustrated in FIG. 2, a small cell that performs intermittent transmission may be selected based on the number of edge users of the damaged cells of each small cell.

  Specifically, one cell having the largest number of edge users of the damaged cell may be selected as a small cell that performs intermittent transmission. In this case, the number of edge users of the damaged cells of each small cell may be simply compared, and the small cell having the largest number of edge users of the damaged cell may be selected as the small cell that performs intermittent transmission.

  Alternatively, some small cells may be selected from among the plurality of small cells as small cells that perform intermittent transmission. The selection can be made by various methods. In the first exemplary method, the plurality of small cells are arranged according to the number of edge users of the damaged cells, and the small cells that intermittently transmit several small cells from the small cells having the largest number of edge users of the damaged cells. You may choose as In the second exemplary method, among the plurality of small cells, at least one small cell having the largest number of edge users of the damaged cell and satisfying a predetermined condition is sequentially selected as a small cell for intermittent transmission. May be. Compared with the method described using FIGS. 3 and 4 above, the second exemplary method uses the number of damaged cells in the method described using FIGS. 3 and 4 as the number of edge users of the damaged cells. Only the point of replacement is different, and the remaining operations are the same. Therefore, detailed description is omitted here to avoid duplication.

  The other contents of the modification method are the same as those of the first embodiment, and will not be described here.

  Hereinafter, a device for selecting a small cell for intermittent transmission from among a plurality of small cells according to the first embodiment of the present invention will be described with reference to FIG. The device may be included in the eNodeB shown in FIG. 1 and is operably coupled to each BBU in the BBU pool and functions as the above-described small cell controller. The device may be located elsewhere, for example, located outside the eNodeB and operably coupled to a BBU pool in the eNodeB so that information can be exchanged. Further, although the device can execute the method described above, since the operation executed by the device is substantially the same as each step of the method described above, only the device will be briefly described here.

  As illustrated in FIG. 5, a device 500 that selects a small cell that performs intermittent transmission from among a plurality of small cells includes an information acquisition device 501 and a cell selection device 502.

  The information acquisition apparatus 501 acquires interference information of each small cell in the plurality of small cells, and the interference information of each small cell is related to the other small cells in the plurality of small cells. Indicates the degree of interference. For each small cell, the degree of interference of the small cell with other small cells may be indicated using the number of damaged cells of the small cell, i.e., the interference information of each small cell indicates the damage of the small cell. It may be a value indicating the quantity of cells. As described above, the number of damaged cells in each small cell may be determined based on the reception quality measurement report received from the user of each small cell. For example, the interference information of each small cell may be acquired by acquiring the number of damaged cells of each small cell by the method described with reference to FIG. Omitted.

  The cell selection device 502 selects a small cell that performs intermittent transmission from the plurality of small cells based on the interference information of each small cell acquired from the information acquisition device 501.

  Specifically, the cell selection device 502 may select one small cell having the largest interference information value from the plurality of small cells as a small cell that performs intermittent transmission. In this case, the cell selection device 502 may simply compare the number of damaged cells of each small cell and select the small cell having the largest number of damaged cells as a small cell that performs intermittent transmission.

  Alternatively, the cell selection device 502 may select some small cells from among the plurality of small cells as small cells that perform intermittent transmission. The cell selection device 502 can perform the selection by various methods. In the first exemplary method, the cell selection device 502 arranges the plurality of small cells according to the number of damaged cells, and intermittently transmits several small cells from among the small cells having the largest number of damaged cells. You may select as a small cell which performs. In the second exemplary method, the cell selection device 502 sequentially selects at least one small cell having the largest number of damaged cells and satisfying a predetermined condition from the plurality of small cells as a cell for intermittent transmission. You may choose. The cell selection device 502 can perform this selection by the method described with reference to FIGS. 3 and 4, and detailed description thereof is omitted here so as not to overlap. It should be noted that, in the above selection process, if multiple small cells have the same number of damaged cells and the number is larger than the number of damaged cells of other small cells, it will be randomly selected. Any one or more of these may be selected, or one or more of them may be selected according to additional criteria, for example, one or more may be selected among them according to the quantity of the central user .

  For small cells other than the selected at least one small cell among the plurality of small cells, the cell selection device 502 may set the small cell to perform normal transmission (that is, continuous transmission). Good. Specifically, when another small cell is currently in the normal transmission state, the cell selection device 502 continues normal transmission without changing the state, and the other small cells are in the current intermittent transmission state. In some cases, the cell selection device 502 may change the state to the normal transmission state and perform normal transmission.

  After selecting at least one small cell that performs intermittent transmission, the cell selection device 502 transmits information indicating the selected at least one small cell in the base station according to one of the plurality of methods described above. You may transmit to the baseband unit corresponding to one small cell. Moreover, the cell selection apparatus 502 may notify the BBU corresponding to information indicating that the transmission state of other small cells should be maintained or changed.

  If the said device is used, the small cell which performs at least 1 intermittent transmission from the said several small cells can be selected. The device can perform intermittent transmission by executing the above method for each transmission interval and selecting an appropriate small cell for each transmission interval.

(Deformation)
In the above, for each small cell in the plurality of small cells, the degree of interference of the small cell with respect to other small cells is shown using the number of damaged cells of the small cell. However, the degree of interference of another small cell with the small cell may be indicated by the number of edge users of the damaged cell of the small cell. In this case, the interference information of each small cell is a value indicating the number of edge users of the damaged cell of the small cell.

  Specifically, the information acquisition device 501 acquires the number of edge users of the damaged cells of each small cell, and uses it as interference information of the small cell. As described above, the information acquisition apparatus 501 may determine the number of edge users of the damaged cells of each small cell based on the reception quality measurement report received from the users of each small cell. For example, the information acquisition apparatus 501 may acquire the number of edge users of the damaged cells of each small cell by the method described above, and detailed description thereof is omitted here so as not to overlap.

  The cell selection device 502 may select a small cell that performs intermittent transmission based on the number of edge users of the damaged cells of each small cell acquired by the information acquisition device 501. Specifically, the cell selection device 502 may select one cell having the largest number of edge users of the damaged cell as a small cell that performs intermittent transmission. Alternatively, the cell selection device 502 may select some small cells from among the plurality of small cells as small cells that perform intermittent transmission. For example, the cell selection device 502 arranges the plurality of small cells according to the number of edge users of the damaged cell, and intermittently transmits several small cells from the small cell having the largest number of edge users of the damaged cell. You may choose as Alternatively, the cell selection device 502 sequentially selects at least one small cell having the largest number of edge users of the damaged cell and satisfying a predetermined condition from the plurality of small cells as a small cell that performs intermittent transmission. Also good. The cell selection device 502 may select a small cell by the method described above, and will not be described here.

  Other contents of the deformation device are the same as those of the device of the first embodiment, and will not be described here.

(Second embodiment)
In the first embodiment of the present invention, the modified method and device thereof, a small cell is selected in consideration of the performance gain that intermittent transmission of the small cell brings to other small cell users. However, as described above, when a small cell performs intermittent transmission, specifically, when the small cell is muted at any transmission interval, the user (particularly the central user) transmits data at the transmission interval. Data cannot be transmitted, data transmission delay occurs, and the performance of the user is degraded. In order to ensure the balance between the performance gain and the performance degradation, a method and device for selecting a cell for intermittent transmission from a plurality of cells according to the second embodiment of the present invention have been proposed.

  Hereinafter, a method and device for selecting a small cell for intermittent transmission from a plurality of small cells according to a second embodiment of the present invention will be described with reference to the drawings. The second embodiment differs from the first embodiment only in the grounds for selecting a small cell for intermittent transmission. Here, for the sake of simplicity, the second embodiment and the first embodiment are the same as the first embodiment in the second embodiment. Detailed description is omitted.

  FIG. 6 is a flowchart showing a method for selecting a small cell for intermittent transmission from a plurality of small cells according to the second embodiment of the present invention. The method may be executed by the eNodeB shown in FIG. For example, the method may be executed by installing a small cell operation controller that is operably coupled to the BBU pool in the eNodeB shown in FIG.

  As shown in FIG. 6, in step S601, the interference information of each small cell in the plurality of small cells and the quantity of users of a predetermined type are acquired. However, the interference information of each small cell indicates the degree of interference of the small cell with respect to other small cells among the plurality of small cells.

  As in the first embodiment, the interference information of each small cell may indicate the number of damaged cells of the small cell, and detailed description thereof is omitted here so as not to overlap.

  The difference from the first embodiment is that in this embodiment, the quantity of users of a predetermined type in each small cell is further acquired. The predetermined type of user may be any type of user determined as necessary. For example, a user (for example, a user who needs to ensure that a small cell performs intermittent transmission to suppress the influence on the service quality as much as possible (for example, High priority users), users who need to ensure that the influence of the throughput or data transmission delay caused by the small cell performing intermittent transmission is minimized. Since the intermittent transmission of the selected small cell adversely affects the predetermined type of user of the small cell, the small cell performs the intermittent transmission according to the quantity of the predetermined type of user of the selected small cell. Thus, it is possible to show the performance degradation caused to a predetermined type of user. In the present embodiment, the predetermined type of user may be a central user, and in this case, the quantity of central users of each cell is acquired. The number of central users in each cell may be determined by a reception quality measurement report received from the user in each cell. When the first embodiment is described, the method for determining the number of central users of each cell has been described, so that it will not be described here.

  Next, in step S602, a cell for intermittent transmission is selected from the plurality of cells based on the interference information of each cell acquired in step S601 and the number of users of a predetermined type.

  Specifically, first, a difference d = N−a × M corresponding to each small cell may be calculated, where N is a value of interference information of the small cell (in this embodiment, a damaged cell). M is a quantity of a predetermined type of user of the small cell, and a is an adjustment coefficient. The difference d reflects the level of performance improvement provided to the entire communication system by the intermittent transmission of the small cell. The value of the adjustment coefficient a may be set flexibly according to actual needs. Typically, a may be set to 0 <a ≦ 1. For example, a may be set to 1. In this case, the difference d corresponding to each small cell is a difference between the number of damaged cells of the small cell and the number of central users of the small cell. Alternatively, since the quantity M of the predetermined type of user is usually larger than the quantity N of the damaged cells, it is selected by setting a to another value smaller than 0.5 or 1 to reduce the weight of M. Small cells may be made more rational.

  Thereafter, at least one small cell that performs intermittent transmission may be selected based on the difference d. For example, one small cell corresponding to the maximum difference d may be selected from the plurality of small cells as a small cell that performs intermittent transmission. In this case, the difference d corresponding to each small cell may be simply compared, and one small cell having the largest difference d may be selected as a small cell for intermittent transmission. Alternatively, at least one small cell corresponding to the largest difference d and satisfying a predetermined condition among the plurality of small cells may be sequentially selected as a small cell that performs intermittent transmission. In this case, the selection can be performed by various methods. In the first method, the plurality of small cells may be arranged according to the size of the difference d, and at least one cell may be selected as a cell for intermittent transmission from the small cells having the largest difference d. In the second method, among the plurality of small cells, at least one small cell corresponding to the largest difference d and satisfying a predetermined condition may be sequentially selected as a small cell for intermittent transmission. The second method described for the second method and the first embodiment replaces the number of damaged cells used in the second method described for the first embodiment with the difference d. Since only the points are different, detailed description is omitted here so as not to overlap.

  The small cells other than the selected at least one small cell in the plurality of cells may be set to perform normal transmission (that is, continuous transmission or non-intermittent transmission) as described above. . In addition, after selecting at least one small cell that performs intermittent transmission, using any one of the plurality of methods, information indicating the selected at least one small cell is transmitted in the base station to the at least one small cell Information indicating that it should be transmitted to the baseband unit corresponding to the small cell and the transmission state of other small cells should be maintained or changed may be notified to the corresponding BBU. Each BBU can control intermittent transmission or normal transmission of a corresponding small cell based on the received information.

(Deformation)
In the second embodiment, for each small cell of the plurality of small cells, the number of damaged cells of the small cell is used to indicate the degree of interference with the other small cells. It was. However, you may show the interference degree with respect to the other small cells by the quantity to the edge user of the damage cell of the said small cell.

  Specifically, in the modification, in step S601 shown in FIG. 6, the number of edge users of the damaged cells of each small cell is acquired and used as interference information of the small cell, that is, the interference information of each small cell. Is a value indicating the number of edge users in the damaged cell of the small cell, and also acquires the quantity of a predetermined type of user in each small cell. The method for obtaining the quantity is the same as that described above with reference to the first and second embodiments, and will not be described here.

  Thereafter, in step S602 illustrated in FIG. 6, a small cell that performs intermittent transmission may be selected based on the number of edge users of the damaged cell of each small cell and the number of users of a predetermined type.

  In this case, first, the difference d = N′−a × M corresponding to each small cell may be calculated, where N ′ is the interference information value of the small cell (in this modification, The number of edge users), M is the number of users of a predetermined type of the small cell, and a is an adjustment coefficient. Similarly, a may be set to 0 <a ≦ 1. For example, a may be set to 1 or 0.5.

  Thereafter, at least one small cell that performs intermittent transmission may be selected based on the difference d. For example, one cell corresponding to the maximum difference d may be selected as a cell for intermittent transmission from the plurality of cells. Alternatively, at least one small cell corresponding to the largest difference d and satisfying a predetermined condition among the plurality of small cells may be sequentially selected as a small cell that performs intermittent transmission. Since this selection operation is the same as the method described with reference to FIG. 6, detailed description thereof is omitted here.

  The other contents of the modification method are the same as those of the second embodiment, and will not be described here.

  Hereinafter, a device for selecting a small cell that performs intermittent transmission from among a plurality of small cells according to a second embodiment of the present invention will be described. The device may be included in the eNodeB shown in FIG. 1 and is operably coupled to each BBU in the BBU pool and functions as the above-described small cell controller. The device may be located elsewhere, for example, located outside the eNodeB and operably coupled to a BBU pool in the eNodeB so that information can be exchanged. In addition, the device can execute the method according to the second embodiment of the present invention described above, but the operation executed by the device is substantially the same as each step in the method according to the second embodiment described above. Therefore, only the device will be briefly described here.

  As illustrated in FIG. 7, a device 700 that selects a small cell that performs intermittent transmission from a plurality of small cells includes an information acquisition device 701 and a cell selection device 702.

  The information acquisition device 701 acquires the interference information of each small cell in the plurality of small cells and the quantity of a predetermined type of user, and the interference information of each small cell indicates that the small cell has the plurality of small cells. The interference degree with respect to other small cells in the inside is shown. Similarly, for each small cell, the degree of interference of the small cell with respect to other small cells may be indicated using the number of damaged cells of the small cell. That is, the interference information of each small cell is It may be a value indicating the number of damaged cells of the cell. By the above method, the number of damaged cells in each small cell may be determined from the reception quality measurement report received from the user of each small cell. Further, the quantity of the predetermined type of user may be determined by the above method. In this embodiment, the predetermined type of user may be a central user.

  The cell selection device 702 selects a small cell that performs intermittent transmission from the plurality of small cells based on the interference information of each small cell acquired from the information acquisition device 701 and the quantity of a predetermined type of user.

  Specifically, the cell selection device 702 may first calculate a difference d = N−a × M corresponding to each small cell, where N is a value of interference information of the small cell (this embodiment) In the example, the number of damaged cells), M is the number of users of a predetermined type of the small cell, and a is an adjustment coefficient. The value of the adjustment coefficient a may be set flexibly according to actual needs. Typically, a may be set to 0 <a ≦ 1. For example, a may be set to 1 or 0.5. Thereafter, the cell selection device 702 may select at least one small cell that performs intermittent transmission based on the difference d. For example, the cell selection device 702 may select one small cell corresponding to the maximum difference d from the plurality of small cells as a small cell that performs intermittent transmission. Alternatively, the cell selection device 702 sequentially selects at least one small cell corresponding to the maximum difference d and satisfies a predetermined condition from the plurality of small cells as a small cell that performs intermittent transmission. Also good.

  As for the small cells other than the selected at least one small cell in the plurality of small cells, the cell selection device 702 normally transmits the small cell (that is, continuous transmission or non-transmission) as described above. (Intermittent transmission) may be set. In addition, after selecting at least one small cell that performs intermittent transmission, the cell selection device 702 performs information indicating at least one selected small cell by any one of the plurality of methods described above. The base station may transmit information to the baseband unit corresponding to the at least one small cell, and notify the BBU corresponding to the information indicating that the transmission state of the other small cells should be maintained or changed. Each BBU can control intermittent transmission or normal transmission of the corresponding small cell based on the received information.

  In the second embodiment of the present invention, when selecting a small cell for intermittent transmission, simultaneously the performance gain that the intermittent transmission of the small cell brings to the user of another small cell and the performance loss of the user of the small cell itself. For consideration, intermittent transmission of selected small cells can significantly reduce the interference between small cells, and at the same time improve the overall performance of the communication system by preventing the user performance from being significantly affected.

(Deformation)
In the device 700, for each small cell in the plurality of small cells, the degree of interference of the small cell with respect to other small cells is indicated using the number of damaged cells of the small cell. However, the degree of interference of another small cell with the small cell may be indicated by the number of edge users of the damaged cell of the small cell. In this case, the interference information of each small cell is a value indicating the number of edge users of the damaged cell of the small cell.

  Specifically, the information acquisition apparatus 701 acquires the number of edge users of the damaged cells of each small cell, and uses it as interference information of the small cell. The information acquisition device 701 also acquires the quantity of a predetermined type of user in each small cell.

  The cell selection device 702 may select a small cell that performs intermittent transmission based on the number of edge users of the damaged cell of each small cell acquired by the information acquisition device 701 and the number of users of a predetermined type.

  In this case, first, the cell selection device 702 may calculate a difference d = N′−a × M corresponding to each small cell, where N ′ is a value of interference information of the small cell (this modification). Is the quantity of edge users of the damaged cell), M is the quantity of a predetermined type of user of the small cell, and a is an adjustment coefficient. Similarly, typically, a may be set to 0 <a ≦ 1. For example, a may be set to 1 or 0.5.

  Thereafter, the cell selection device 702 may select at least one small cell that performs intermittent transmission based on the difference d. For example, the cell selection device 702 may select one small cell corresponding to the maximum difference d from the plurality of small cells as a small cell that performs intermittent transmission. Alternatively, the cell selection device 702 sequentially selects at least one small cell corresponding to the largest difference d and satisfies a predetermined condition from the plurality of small cells as a small cell that performs intermittent transmission. Also good. Since this selection operation is the same as the method described with reference to FIG. 6, detailed description thereof is omitted here.

  The other contents of the deformation device are the same as the method of the second embodiment and will not be described here.

(Third embodiment)
In the third embodiment of the present invention, a small cell that performs intermittent transmission may be selected based only on the number of users of a predetermined type of each small cell.

  Hereinafter, a method and device for selecting a small cell for intermittent transmission from a plurality of small cells according to a third embodiment of the present invention will be described with reference to the drawings. Since the third embodiment differs from the first and second embodiments only in the grounds for selecting a small cell for intermittent transmission, here, for simplicity, the first and second embodiments in the third embodiment A description of the same details as in the second embodiment will be omitted.

  FIG. 8 is a flowchart showing a method for selecting a small cell for intermittent transmission from a plurality of small cells according to the third embodiment of the present invention. The method may be performed by the eNodeB shown in FIG. For example, the method may be executed by installing a small cell operation controller that is operably coupled to the BBU pool in the eNodeB shown in FIG.

  As shown in FIG. 8, in step S801, the number of users of a predetermined type in each small cell of the plurality of small cells is acquired. The user of the predetermined type may be any type of user determined as necessary. For example, a user who needs to ensure that a small cell performs intermittent transmission to minimize the influence on the service quality. It may be a user who needs to ensure that the influence of the cell on the throughput or the delay of data transmission is suppressed as much as possible by performing intermittent transmission. In this embodiment, the predetermined type of user may be a central user.

  Next, in step S802, a cell for intermittent transmission is selected from the plurality of cells based on the number of users of a predetermined type in each cell acquired in step S801.

  Specifically, one small cell with the smallest number of predetermined types of users may be selected as a small cell for intermittent transmission from the plurality of small cells. Alternatively, at least one small cell having the smallest number of predetermined types of users may be sequentially selected as a small cell for intermittent transmission from the plurality of small cells. The selection operation may be performed in the same manner in step S802 by the methods described above with reference to FIG. 2, and detailed description thereof is omitted here so as not to overlap.

  As for the small cells other than the selected at least one small cell in the plurality of small cells, normal transmission (that is, continuous transmission or non-intermittent transmission) of the small cell is performed as described above. It may be set. In addition, after selecting at least one small cell for intermittent transmission, information indicating the selected at least one small cell is transmitted to the at least one small cell by any one of the plurality of methods described above. Information transmitted to the baseband unit corresponding to one small cell and instructing that the transmission state of the other small cell should be maintained or changed may be notified to the corresponding BBU. Each BBU can control intermittent transmission or normal transmission of the corresponding small cell based on the received information.

  Hereinafter, a device for selecting a small cell that performs intermittent transmission from among a plurality of small cells according to a third embodiment of the present invention will be described. The device may be included in the eNodeB shown in FIG. 1 and is operably coupled to each BBU in the BBU pool and functions as the above-described small cell controller. The device may be located elsewhere, for example, located outside the eNodeB and operably coupled to a BBU pool in the eNodeB so that information can be exchanged. The device can also execute the method according to the third embodiment of the present invention described above.

  As illustrated in FIG. 9, a device 900 that selects a small cell that performs intermittent transmission from a plurality of small cells includes an information acquisition device 901 and a cell selection device 902.

  The information acquisition device 901 acquires the number of users of a predetermined type in each small cell among the plurality of small cells. The user of the predetermined type may be any type of user determined as necessary. For example, a user who needs to ensure that a small cell performs intermittent transmission to minimize the influence on the service quality. It may be a user who needs to ensure that the influence of the throughput or data transmission delay caused by intermittent transmission of cells is minimized. In this embodiment, the predetermined type of user may be a central user.

  The cell selection device 902 selects a cell to be intermittently transmitted from the plurality of cells based on the quantity of users of a predetermined type of each cell acquired by the information acquisition device 901.

  Specifically, the cell selection device 902 may select one small cell having the smallest number of users of a predetermined type as the small cell performing intermittent transmission from the plurality of small cells. Alternatively, the cell selection device 902 sequentially selects at least one small cell having the smallest number of predetermined types of users and satisfying a predetermined condition from the plurality of small cells as a small cell that performs intermittent transmission. May be. The cell selection device 902 may perform this selection operation in the same manner by the methods described above with reference to FIG. 2, and detailed description thereof will not be repeated here.

  As for the small cells other than the selected at least one small cell among the plurality of small cells, the cell selection device 902 normally transmits the small cell (that is, continuous transmission or non-transmission). (Intermittent transmission) may be set. In addition, after selecting at least one small cell that performs intermittent transmission, the cell selection device 902 performs information indicating at least one selected small cell by any one of the plurality of methods described above. The base station may transmit information to the baseband unit corresponding to the at least one small cell, and notify the BBU corresponding to the information indicating that the transmission state of the other small cells should be maintained or changed. Each BBU can control intermittent transmission or normal transmission of the corresponding small cell based on the received information.

  Thus, by using the method and device according to the third embodiment of the present invention, an appropriate small cell can be selected and intermittent transmission can be performed, thereby reducing interference between the small cells and the entire communication system. To prevent the performance of the product from being significantly adversely affected.

  In the first to third embodiments of the present invention and modifications thereof, when selecting a small cell for intermittent transmission, one or several small cells are selected to intermittently transmit excessively frequently. The data transmission of the user of the selected small cell may be significantly delayed, and the performance of the selected small cell may be significantly deteriorated. In order to avoid such a situation, the intermittent transmission history frequency of each cell (that is, the number and time of intermittent transmissions in the past predetermined time zone) may be acquired. The small cell that performs intermittent transmission is selected based on the above. Specifically, after selecting a small cell that performs intermittent transmission using the method and device described above and its modifications, it is further determined whether the intermittent transmission history frequency of the selected small cell has exceeded a predetermined threshold. It may be confirmed. When the predetermined threshold value is exceeded, the selection result of the current small cell is discarded, that is, the selected cell is selected by using the above method and device and its modification without intermittent transmission to the currently selected small cell. Until the intermittent transmission history frequency of the small cell does not exceed a predetermined threshold, the small cell that performs intermittent transmission again from among the small cells other than the currently selected small cell among the plurality of small cells. select. In this case, the small cell that is finally selected to perform intermittent transmission is a small cell whose intermittent transmission history frequency does not exceed a predetermined threshold.

(Fourth embodiment)
In the fourth embodiment of the present invention, a small cell that performs intermittent transmission is selected based only on the intermittent transmission history frequency of each small cell.

  Hereinafter, a method and device for selecting a small cell for intermittent transmission from a plurality of small cells according to a fourth embodiment of the present invention will be described with reference to the drawings. The fourth embodiment is different from the first, second, and third embodiments only in the grounds for selecting a small cell that performs intermittent transmission. Here, for simplification, the fourth embodiment is the same as that in the fourth embodiment. A description of the same details as those of the first, second and third embodiments will be omitted.

  FIG. 10 is a flowchart showing a method for selecting a small cell for intermittent transmission from a plurality of small cells according to the fourth embodiment of the present invention. The method may be performed by the eNodeB shown in FIG. For example, the method may be executed by installing a small cell operation controller that is operably coupled to the BBU pool in the eNodeB shown in FIG.

  As shown in FIG. 10, in step S1001, the intermittent transmission history frequency of each small cell in the plurality of small cells is acquired. The intermittent transmission history frequency may be represented by, for example, the number of times or time that the cell has performed intermittent transmission within a predetermined time period in the past.

  Next, in step S1002, based on the intermittent transmission history frequency of each cell acquired in step S1001, a cell that performs intermittent transmission is selected from the plurality of cells.

  Specifically, one small cell having the lowest intermittent transmission history frequency may be selected from the plurality of small cells as a small cell that performs intermittent transmission. Alternatively, at least one small cell having the lowest missed transmission history frequency may be sequentially selected as a small cell for intermittent transmission from the plurality of small cells. The selection operation may be performed in the same manner in step S1002 by the methods described above with reference to FIG. 2, and detailed description thereof is omitted here so as not to overlap.

  As for the small cells other than the selected at least one small cell in the plurality of small cells, normal transmission (that is, continuous transmission or non-intermittent transmission) of the small cell is performed as described above. It may be set. In addition, after selecting at least one small cell for intermittent transmission, information indicating the selected at least one small cell by any one of the plurality of methods described above is transmitted in the base station to the at least one small cell. Information transmitted to the baseband unit corresponding to one small cell and instructing that the transmission state of the other small cell should be maintained or changed may be notified to the corresponding BBU. Each BBU can control intermittent transmission or normal transmission of the corresponding small cell based on the received information.

  Hereinafter, a device for selecting a small cell that performs intermittent transmission from among a plurality of small cells according to a fourth embodiment of the present invention will be described. The device may be included in the eNodeB shown in FIG. 1 and is operably coupled to each BBU in the BBU pool and functions as the above-described small cell controller. The device may be located elsewhere, for example, located outside the eNodeB and operably coupled to a BBU pool in the eNodeB so that information can be exchanged. The device can also execute the method according to the fourth embodiment of the present invention described above.

  As illustrated in FIG. 11, a device 1100 that selects a small cell that performs intermittent transmission from a plurality of small cells includes an information acquisition device 1101 and a cell selection device 1102.

  The information acquisition apparatus 1101 acquires the intermittent transmission history frequency of each small cell in the plurality of small cells.

  The cell selection device 1102 selects a cell to be intermittently transmitted from the plurality of cells based on the intermittent transmission history frequency of each cell acquired by the information acquisition device 1101.

  Specifically, the cell selection apparatus 1102 may select one small cell having the lowest intermittent transmission history frequency as the small cell performing intermittent transmission from the plurality of small cells. Alternatively, the cell selection device 1102 may sequentially select at least one small cell having the lowest intermittent transmission history frequency from the plurality of small cells as a small cell that performs intermittent transmission. The cell selection apparatus 1102 may perform this selection operation in the same manner by the methods described above with reference to FIG. 2, and detailed description thereof will not be repeated here.

  As for the small cells other than the selected at least one small cell among the plurality of small cells, the cell selection device 1102 normally transmits the small cells (that is, continuous transmission or non-transmission). (Intermittent transmission) may be set. In addition, after selecting at least one small cell that performs intermittent transmission, the cell selection device 1102 performs information indicating at least one selected small cell by any one of the plurality of methods described above. The base station may transmit information to the baseband unit corresponding to the at least one small cell, and notify the BBU corresponding to the information indicating that the transmission state of the other small cells should be maintained or changed. Each BBU can control intermittent transmission or normal transmission of the corresponding small cell based on the received information.

  Thus, by using the method and device according to the fourth embodiment of the present invention, a cell to be intermittently transmitted is selected for each transmission interval, and at the same time, any one or several cells perform intermittent transmission excessively frequently. It is possible to avoid being selected and to prevent a significant deterioration in its performance.

  The method and device for selecting a cell for intermittent transmission from a plurality of cells according to embodiments of the present invention have been described above. It should be noted that these descriptions are illustrative and not limiting. Those skilled in the art can make various changes to this without departing from the scope of the present invention. For example, in the above, the embodiment of the present invention has been described in the C-RAN configuration, but the present invention is not limited to this, and may be applied to any other configuration different from the C-RAN configuration. Further, as described above, the present invention may be applied to other types of cells other than the small cells.

While exemplary embodiments of the present invention have been shown and described, it should be understood by those skilled in the art without departing from the scope and spirit of the invention as defined in the appended claims and equivalents thereof. Various types and details of changes may be made to the exemplary embodiment.

Claims (14)

A method of selecting a cell for intermittent transmission from a plurality of cells,
Obtaining at least one of the interference information of each cell of the plurality of cells, the quantity of a predetermined type of user of each cell and the intermittent transmission history frequency of each cell; The cell interference information indicates the degree of interference of the cell with other cells in the plurality of cells,
Selecting a cell to perform at least one intermittent transmission from among the plurality of cells based on at least one of interference information of each cell, a quantity of a predetermined type of user, and an intermittent transmission history frequency. Method. The interference information of each cell is a value indicating the number of damaged cells of the cell or the number of edge users of the damaged cell of the cell, and the damaged cell receives interference of the cell among the plurality of cells. When selecting a cell that performs at least one intermittent transmission from the plurality of cells based on interference information of each cell,
The method according to claim 1, wherein at least one cell having the largest interference information value and satisfying a predetermined condition is sequentially selected as a cell for intermittent transmission from the plurality of cells. The interference information of each cell is a value indicating the number of damaged cells of the cell or the number of edge users of the damaged cell of the cell, and the damaged cell receives interference of the cell among the plurality of cells. When selecting a cell that performs at least one intermittent transmission from the plurality of cells based on the interference information of each cell and the number of users of the predetermined type,
The difference d = N−a × M corresponding to each cell is calculated, where N is the value of the interference information of the cell, M is the quantity of a predetermined type of user of the cell, and a is an adjustment coefficient. Yes,
The method according to claim 1, wherein at least one cell corresponding to the largest difference d and satisfying a predetermined condition is sequentially selected as a cell for intermittent transmission from the plurality of cells. When selecting a cell to perform intermittent transmission from among the plurality of cells based on the number of users of a predetermined type of each cell,
The method according to claim 1, wherein a cell having the smallest number of predetermined types of users is selected as a cell for intermittent transmission from the plurality of cells.   The method according to any one of claims 2 to 4, wherein the selected cell is a cell whose intermittent transmission history frequency does not exceed a predetermined threshold. When selecting a cell that performs at least one intermittent transmission from the plurality of cells based on the intermittent transmission history frequency of each cell,
The method according to claim 1, wherein at least one cell having the lowest intermittent transmission history frequency is sequentially selected from the plurality of cells as a cell for performing intermittent transmission.   The method is executed in a base station of a centralized radio access network, and transmits information indicating a selected cell for performing at least one intermittent transmission to a baseband unit corresponding to the at least one cell in the base station. Item 7. The method according to any one of Items 1 to 6. A device for selecting a cell for intermittent transmission from a plurality of cells,
An information acquisition device for acquiring at least one of interference information of each cell in the plurality of cells, a quantity of users of a predetermined type of each cell, and an intermittent transmission history frequency of each cell; The interference information of each cell indicates the degree of interference with respect to other cells in the plurality of cells.
A cell selection device that selects a cell that performs at least one intermittent transmission from among the plurality of cells, based on at least one of interference information of each cell, the quantity of a predetermined type of user, and an intermittent transmission history frequency; Including device. The interference information of each cell is a value indicating the number of damaged cells of the cell or the number of edge users of the damaged cell of the cell, and the damaged cell receives interference of the cell among the plurality of cells. Cell,
When selecting a cell for performing at least one intermittent transmission from the plurality of cells based on the interference information of each cell, the cell selection device has the largest interference information value from the plurality of cells. The device according to claim 8, wherein at least one cell satisfying a predetermined condition is sequentially selected as a cell for intermittent transmission. The interference information of each cell is a value indicating the number of damaged cells of the cell or the number of edge users of the damaged cell of the cell, and the damaged cell receives interference of the cell among the plurality of cells. Cell,
When selecting a cell that performs at least one intermittent transmission from among the plurality of cells based on the interference information of each cell and the quantity of users of the predetermined type, the cell selection device uses a difference corresponding to each cell. d = N−a × M is calculated, and at least one cell corresponding to the largest difference d and satisfying a predetermined condition among the plurality of cells is sequentially selected as a cell for intermittent transmission, where N is The device according to claim 8, wherein the interference information value of the cell, M is a quantity of a predetermined type of user of the cell, and a is an adjustment coefficient.   When selecting a cell to be intermittently transmitted from the plurality of cells based on the number of users of a predetermined type in each cell, the cell selection device has the largest number of users of a predetermined type from the plurality of cells. The device according to claim 8, wherein a small number of cells are selected as cells for intermittent transmission.   The method according to claim 9, wherein the cell selected by the cell selection device is a cell whose intermittent transmission history frequency does not exceed a predetermined threshold.   When selecting a cell for performing at least one intermittent transmission from the plurality of cells based on the intermittent transmission history frequency of each cell, the cell selection device selects the lowest intermittent transmission history frequency from the plurality of cells. The device according to claim 8, wherein at least one cell is selected in order as a cell for intermittent transmission. The device is included in a base station of a centralized radio access network, and the cell selection device corresponds to the at least one cell in the base station information indicating at least one selected cell for intermittent transmission. The device according to any one of claims 8 to 13, wherein the device transmits to a baseband unit.