JPWO2019167127A1 - Connection control device, wireless communication control device, wireless communication system, base station, wireless communication method, and connection control program - Google Patents

Abstract

The wireless communication system (100) includes a terminal (200), a base station (300), and a wireless communication control device (400) corresponding to a connection control device. The acquisition unit (510) of the wireless communication control device (400) acquires information for the control unit (520) of the terminal (200) to determine the length of communication occupied time. The control unit (520) of the wireless communication control device (400) is formed by the base station (300) according to the length of communication occupied time, which is the time when the terminal (200) occupies the channel of wireless communication. Select one cell from a plurality of overlapping cells. The control unit (520) controls the connection of the terminal (200) to the selected cell.

Description

  The present invention relates to a connection control device, a wireless communication control device, a wireless communication system, a base station, a wireless communication method, and a connection control program.

  In recent years, various wireless standards have appeared and are being used for various purposes. For example, in a wireless LAN, various services utilizing the convenience of wireless communication are performed using frequencies in the 2.4 GHz band and the 5 GHz band. “LAN” is an abbreviation for Local Area Network. Services using the frequency of the 2.4 GHz band are crowded due to increased use of users, and in many cases, sufficient services cannot be received. For this reason, efforts are being made to shift to the 5 GHz band, which currently has fewer users than the 2.4 GHz band. For example, IEEE 802.11ac, which is a wireless LAN standard completed in 2013, is a wireless LAN standard defined only in the 5 GHz band.

  In accordance with this situation, the latest wireless LAN base station employs not only a dual configuration capable of simultaneous communication in the 2.4 GHz band and the 5 GHz band, but also one of the dual wireless functions. There are devices that have a wireless function in the 5 GHz band and the other wireless function in the 2.4 GHz or 5 GHz band. In such a wireless LAN base station, a single base station can perform simultaneous communication in 5 GHz band × 2 in addition to simultaneous communication in the 2.4 GHz band and 5 GHz band. Therefore, a service can be provided simultaneously in a plurality of cells using a plurality of frequencies in the 5 GHz band in the same area.

  As terminals connected to the base station, terminals having various wireless LAN performances and standards, such as notebook PCs, tablets, smartphones, and wireless IP phones, have appeared and become available. “PC” is an abbreviation for Personal Computer. “IP” is an abbreviation for Internet Protocol. When accommodating a wide variety of terminals in a wireless LAN system and providing a service, depending on the position of the terminal connected to the base station and the surrounding environment, the corresponding wireless LAN standard, and the difference in the wireless performance such as the number of streams and the bandwidth, The transmission speed of the terminal takes various values.

  Patent Literature 1 discusses a method of changing the transmission speed of wireless communication in order to reliably perform communication when a communication condition is deteriorated due to the position of a terminal connected to a base station and the surrounding environment.

JP 2009-141909 A

  When the conventional technology is used, the transmission speed changes depending on the position of the terminal connected to the base station and the difference in the surrounding environment, and a plurality of terminals having different communication occupation times coexist. A terminal having a low transmission rate has a longer physical frame length than a terminal having a high transmission rate, and has a higher time occupancy during communication. Therefore, there arises a problem that the transmission opportunity of a terminal having a high transmission rate decreases and the system throughput decreases.

  In a conventional wireless LAN system, connection to a base station is performed under the initiative of a terminal. Therefore, even when two cells having different frequencies are arranged in one communication area, various terminals arbitrarily select a cell, and a plurality of terminals having different transmission speeds coexist in the same cell due to a difference in radio propagation environment. A situation arises. Therefore, there is still a problem that the transmission opportunity of the high-speed terminal decreases due to the presence of the low-speed terminal, and the system throughput decreases.

  An object of the present invention is to suppress a decrease in system throughput of wireless communication.

A connection control device according to one embodiment of the present invention,
One of a plurality of cells formed by the base station and overlapping each other according to the length of communication occupation time, which is the time during which the wireless communication channel is occupied by a terminal performing wireless communication via the base station. And a control unit that performs control to connect the terminal to the selected cell,
An acquisition unit is provided for the terminal to acquire information for the control unit to determine the length of the communication occupation time.

  In the present invention, a terminal performing wireless communication via a base station is connected to a cell selected according to the length of the communication occupation time. Therefore, according to the present invention, it is possible to suppress a decrease in system throughput of wireless communication.

FIG. 1 is a diagram showing a configuration of a wireless communication system according to Embodiment 1. FIG. 2 is a block diagram showing a configuration of each device of the wireless communication system according to the first embodiment. 9 is a table showing an example of definitions of a high-speed terminal and a low-speed terminal according to Embodiment 1. FIG. 3 is a diagram showing an example of a cell configuration in the wireless communication system according to the first embodiment. FIG. 2 is a block diagram showing a configuration of the wireless communication control device according to the first embodiment. 5 is a flowchart showing a control flow of the wireless communication system according to the first embodiment. FIG. 4 is a sequence diagram showing a control procedure of the wireless communication system according to the first embodiment. The figure which shows the case 1 which is a comparative example, and the case 2 which is an Example. The figure which shows the case 2 and the case 3 which are an Example. The figure which shows the case 3 and the case 4 which are an Example. 7 is a graph showing an example of throughput evaluation in cases 1 to 4; 9 is a table showing an example of throughput calculation in Cases 1 to 4; 9 is a table showing an example of the number of terminals in Cases 1 to 4; FIG. 9 is a block diagram showing a configuration of each device of the wireless communication system according to the second embodiment. 9 is a table showing an example of definitions of a high-speed terminal and a low-speed terminal according to Embodiment 2. FIG. 9 is a block diagram showing a configuration of a wireless communication control device according to Embodiment 2. 9 is a flowchart showing a control flow of the wireless communication system according to the second embodiment. FIG. 9 is a block diagram showing a configuration of each device of the wireless communication system according to the third embodiment. FIG. 9 is a block diagram showing a configuration of a wireless communication control device according to a third embodiment. FIG. 9 is a block diagram showing a configuration of a base station according to Embodiment 3. 13 is a flowchart showing a control flow of the wireless communication system according to the third embodiment. FIG. 13 is a sequence diagram showing a control procedure of the wireless communication system according to the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the respective drawings, the same or corresponding parts are denoted by the same reference characters. In the description of the embodiments, the description of the same or corresponding portions will be omitted or simplified as appropriate. Note that the present invention is not limited to the embodiments described below, and various modifications can be made as necessary. For example, two or more of the embodiments described below may be implemented in combination. Alternatively, of the embodiments described below, one embodiment or a combination of two or more embodiments may be partially implemented.

Embodiment 1 FIG.
This embodiment will be described with reference to FIGS.

*** Configuration description ***
The overall configuration of wireless communication system 100 according to the present embodiment will be described with reference to FIG. 1 and FIG.

  The wireless communication system 100 corresponds to a terminal 200 that performs wireless communication via the base station 300, a base station 300 that forms a plurality of cells overlapping each other, and a connection control device, and sets the plurality of cells to the base station 300. And a wireless communication control device 400 that performs the processing for

  In the present embodiment, a double cell having a different frequency is constructed in the same service area using the dual configuration of the wireless communication function in base station 300. One cell accommodates a terminal 200 having a short communication occupation time. The other cell accommodates terminal 200 having a long communication occupation time. As a result, even when terminals 200 having different communication occupation times coexist, a decrease in system throughput can be suppressed.

  The wireless communication system 100 may be a system that employs an arbitrary wireless communication system. In the present embodiment, the wireless communication system 100 is a system that employs a wireless LAN system, specifically, a system that employs IEEE802.11ac. The transmission speed may be fixed, but is variable in the present embodiment. A terminal 200 with a high transmission rate, that is, a high-speed terminal, is defined as a terminal 200 with a short communication occupation time. A terminal 200 having a low transmission rate, that is, a low-speed terminal is defined as a terminal 200 having a long communication occupation time. By accommodating a high-speed terminal and a low-speed terminal in different cells, a decrease in system throughput is suppressed.

  The wireless communication control device 400 is connected to a plurality of base stations 300. The wireless communication control device 400 performs arrangement management and frequency control of each base station 300. The base station 300 includes a first radio unit 310 and a second radio unit 320 having a dual configuration as radio function elements. The base station 300 can build a double cell. Note that a base station having three or more wireless function elements may be installed to construct a triple or more cell. Alternatively, multiple cells may be constructed by installing a plurality of base stations each having one wireless functional element. A plurality of terminals 200 are arranged in a cell configured by each base station 300. The wireless communication control device 400 collects information on the connection status such as the type, transmission speed, reception level, and the like of the terminal 200 connected to each base station 300, and communication status.

  In the radio communication system 100 including the radio unit having the dual configuration, the frequency allocation of the base station 300 is performed by repeating one of the four radio frequencies f1, f2, f3, and f4, and the other by assigning the four radio frequencies f5, f6, and f7. And f8 are repeated. One base station 300 configures two cells having different frequencies with the first wireless unit 310 and the second wireless unit 320 having a dual configuration. For example, the base station BS1 configures cells using frequencies f1 and f5, the base station BS2 configures frequencies f2 and f6, the base station BS3 configures frequencies f3 and f7, and the base station BS4 configures cells using frequencies f4 and f8. After constructing a double cell by base station 300 in the same service area, radio communication control apparatus 400 determines whether terminal 200 connects to the cell of first radio section 310 or the cell of second radio section 320. Is determined.

  FIG. 3 shows an example of the definition of the high-speed terminal and the low-speed terminal, and FIG. 4 shows an example of the cell configuration.

  In the example of FIG. 3, a high-speed terminal and a low-speed terminal are defined by the reception sensitivity of IEEE802.11ac. MCS is an index of a combination of a modulation scheme and a coding rate. “MCS” is an abbreviation for Modulation and Coding Scheme. The threshold R for discriminating between the high-speed terminal and the low-speed terminal based on the reception level is set to -72 dBm. As described later, according to the number of terminals in the high-speed terminal accommodation cell and the low-speed terminal accommodation cell, the number of terminals in each cell is set by adaptively changing the threshold R for discrimination between the high-speed terminal and the low-speed terminal. Adjusted to be a ratio. Note that the wireless communication bandwidth is 20 MHz.

  Based on the definition of the high-speed terminal and the low-speed terminal in FIG. 3, as shown in FIG. 4, the terminal 200 that is assumed to have a high reception level and a high transmission speed has an SSID composed of cells of the first wireless unit 310. Connect to the "A" network. The terminal 200 assumed to have a low reception level and a low transmission speed connects to the network having the SSID “B” configured by the cells of the second wireless unit 320. “SSID” is an abbreviation for Service Set ID. “ID” is an abbreviation for Identifier. If the reception level of the terminal 200 is unknown at the time of initial connection, the wireless communication control device 400 connects the terminal 200 to one of the networks, and then periodically measures the reception level of each terminal 200 during communication, Change the connection destination according to the reception level. In the present embodiment, the reception level measurement interval, the averaging period, and the terminal connection control interval are variable. Therefore, it is possible to adjust the change frequency of the terminal connection destination. In the present embodiment, the threshold for distributing high-speed terminals and low-speed terminals is also variable. Therefore, it is possible to periodically measure the number of terminals 200 connected to each cell and perform control so that the number of terminals 200 in each cell becomes the set ratio.

  The configuration of wireless communication control apparatus 400 according to the present embodiment will be described with reference to FIGS.

  The wireless communication control device 400 is a computer. The wireless communication control device 400 includes a processor 401 and other hardware such as a memory 402, an input interface 403, and an output interface 404. The processor 401 is connected to other hardware via a signal line, and controls the other hardware.

  The wireless communication control device 400 includes a setting unit 410 and a terminal accommodation cell switching unit 500 as functional elements. The terminal accommodation cell switching unit 500 includes an acquisition unit 510, a control unit 520, a measurement unit 530, and an adjustment unit 540. That is, the wireless communication control device 400 corresponding to the connection control device includes the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540. The functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 are realized by software.

  The processor 401 is a device that executes a wireless communication control program. The wireless communication control program corresponds to a connection control program, and is a program that implements the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540. The processor 401 is, for example, a CPU, a DSP, or a combination thereof. “CPU” is an abbreviation for Central Processing Unit. “DSP” is an abbreviation for Digital Signal Processor.

  The memory 402 is a device that stores a wireless communication control program. The memory 402 is, for example, a RAM, a flash memory, or a combination thereof. “RAM” is an abbreviation for Random Access Memory.

  The input interface 403 is an interface for receiving data input to the wireless communication control program. The input interface 403 is, for example, a communication chip or an NIC. “NIC” is an abbreviation for Network Interface Card.

  The output interface 404 is an interface for transmitting data output from the wireless communication control program. The output interface 404 is, for example, a communication chip or an NIC.

  Note that the communication interface between the wireless communication control device 400 and the base station 300 may be wired or wireless.

  The wireless communication control program is read from the memory 402 by the processor 401 and executed by the processor 401. The memory 402 stores not only a wireless communication control program but also an OS. “OS” is an abbreviation for Operating System. The processor 401 executes the wireless communication control program while executing the OS. Note that part or all of the wireless communication control program may be incorporated in the OS.

  The wireless communication control program and the OS may be stored in the auxiliary storage device. The auxiliary storage device is, for example, an HDD, a flash memory, or a combination thereof. “HDD” is an abbreviation for Hard Disk Drive. When stored in the auxiliary storage device, the wireless communication control program and the OS are loaded into the memory 402 and executed by the processor 401.

  The wireless communication control device 400 may include a plurality of processors instead of the processor 401. The plurality of processors share execution of the wireless communication control program. Each processor is, for example, a CPU, a DSP, or a combination thereof.

  Data, information, signal values, and variable values used, processed, or output by the wireless communication control program are stored in the memory 402, the auxiliary storage device, or a register or cache memory in the processor 401.

  In the present embodiment, arrangement information 601, frequency information 602, cell information 603, connection information 604, speed determination information 605, reception level information 606, and control information 607 are stored in memory 402. The arrangement information 601 is information on the arrangement of the base station 300. The frequency information 602 is information on the frequency of the base station 300. The cell information 603 is information on a cell of the base station 300. The connection information 604 is information relating to the connection of the terminal 200. The speed determination information 605 is information on the result of determining the transmission speed of the terminal 200. The reception level information 606 is information on the measurement result of the reception level of the terminal 200. The control information 607 is information relating to control of the number of connections of the terminal 200.

  The wireless communication control program causes the computer to execute processing performed by the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 as setting processing, acquisition processing, control processing, measurement processing, and adjustment processing, respectively. It is a program. The wireless communication control program may be provided by being recorded on a computer-readable medium, may be provided by being stored in a recording medium, or may be provided as a program product.

  The wireless communication control device 400 may be configured by one computer, or may be configured by a plurality of computers. When the wireless communication control device 400 includes a plurality of computers, the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 are implemented by being distributed to each computer. Is also good.

*** Explanation of operation ***
The operation of radio communication system 100 according to the present embodiment will be described mainly with reference to FIG. 6 and FIG. The operation of wireless communication system 100 corresponds to the wireless communication method according to the present embodiment.

  In step S11, the setting unit 410 of the wireless communication control device 400 determines whether the reception level of the first wireless unit 310 or the second wireless unit 320 included in the base station 300 is higher than the threshold R for the first wireless unit 310. The frequency of the cell accommodating the terminal is set, and the SSID of the cell is set to “A”.

  In step S12, the setting unit 410 determines, for the second radio unit 320 of the first radio unit 310 and the second radio unit 320 included in the base station 300, The frequency is set, and the SSID of the cell is set to “B”.

  In step S13, acquisition section 510 of wireless communication control apparatus 400 acquires information for control section 520 of terminal 200 to determine the length of communication occupation time. This information includes information indicating the reception level of the wireless communication for the terminal 200. The information acquired by acquisition section 510 may include information indicating the transmission speed of wireless communication for terminal 200 or information indicating the frame length of wireless communication for terminal 200.

Specifically, acquisition section 510 acquires a measured value of the reception level of a signal transmitted from terminal 200. The acquisition unit 510 averages the measured values of the reception level during a certain measurement period T, and calculates the average value X _AVE of the reception levels.

  In step S14, the control unit 520 of the wireless communication control device 400 determines a plurality of cells formed by the base station 300 and overlapping each other according to the length of the communication occupation time, which is the time during which the terminal 200 occupies the wireless communication channel. Select one cell from The control unit 520 performs control for connecting the terminal 200 to the selected cell.

Specifically, control unit 520 accommodates terminal 200 having a high reception level, that is, satisfying X _AVE > R, in a high-speed terminal accommodation cell whose SSID is “A”. Control section 520 accommodates terminal 200 having a low reception level, that is, satisfying X _AVE <R, in a low-speed terminal accommodation cell whose SSID is “B”. The terminal 200 that satisfies X _AVE = R may be accommodated in any cell, but is accommodated in the high-speed terminal accommodation cell in the present embodiment.

  In step S15, the measurement unit 530 of the wireless communication control device 400 measures the number of terminals 200 connected to a plurality of cells formed by the base station 300 and overlapping each other.

  Specifically, measurement section 530 measures the number of terminals 200 connected to each cell of first radio section 310 and second radio section 320.

  In step S16, the adjustment unit 540 of the wireless communication control device 400 determines whether the control unit 520 determines the length of the communication occupation time from the information acquired by the acquisition unit 510 according to the number measured by the measurement unit 530. To adjust.

  Specifically, adjustment section 540 changes reception level threshold value R such that the ratio of the number of connected terminals in each cell becomes the set ratio. That is, assuming that the number of connected terminals of the cell with the SSID “A” is y and the number of connected terminals of the cell with the SSID “B” is z, the adjusting unit 540 sets the ratio of y / z to the set ratio. , The threshold value R is adjusted.

  Steps S13 to S16 are repeatedly executed. The frequency of this repetition may be fixed, but is variable in the present embodiment. That is, acquisition section 510 repeatedly acquires information indicating the reception level of wireless communication for each terminal 200 at a variable frequency. The control unit 520 determines the length of the communication occupation time from the information each time the obtaining unit 510 obtains the information. The control unit 520 selects one cell from a plurality of cells formed by the base station 300 and overlapping each other according to the determined length. If the selected cell is different from the cell to which the corresponding terminal 200 is connected, control unit 520 switches the cell to which terminal 200 is connected.

  The detailed operation of the wireless communication control device 400 will be described.

  The setting information is input to the setting unit 410 from the base station 300 or the operator via the input interface 403. The arrangement information 601 is stored in the memory 402. Setting section 410 determines the frequency of base station 300 based on the arrangement information 601. The frequency is stored in the memory 402 as frequency information 602. The setting unit 410 sets the frequency of the base station 300 via the output interface 404.

  The setting unit 410 sets the reception level of the first radio unit 310 and the second radio unit 320 of the base station 300 to the first radio unit 310 based on the threshold R recorded in the speed determination information 605 of the memory 402. “A” is set via the output interface as the SSID of the cell accommodating the high-speed terminal. The setting is stored in the memory 402 as cell information 603.

  The setting unit 410 sets the reception level of the second radio unit 320 among the first radio unit 310 and the second radio unit 320 included in the base station 300 from the threshold value R recorded in the speed determination information 605 of the memory 402. "B" is set via the output interface as the SSID of the cell accommodating the low-speed terminal. The setting is stored in the memory 402 as cell information 603.

Acquisition section 510 acquires a measured value of the reception level of a signal transmitted from terminal 200 via input interface 403 via base station 300. The acquisition unit 510 averages the measured values of the reception level during a certain measurement period T, and calculates the average value X _AVE of the reception levels. The average value X _AVE is stored in the memory 402 as reception level information 606.

Based on the reception level information 606 stored in the memory 402, the control unit 520 accommodates the terminal 200 whose reception level is high, that is, _XAVE ≧ R, in the high-speed terminal accommodation cell whose SSID is “A”. Control unit 520 accommodates terminal 200 having a low reception level, that is, _XAVE <R, in a low-speed terminal accommodation cell whose SSID is “B”. Connection control for accommodating each terminal 200 in a cell is performed via the output interface 404. The connection status of each terminal 200 is stored in the memory 402 as connection information 604.

  The connection control interval is adjusted by changing the averaging period of the measured value of the reception level, that is, the measurement period T.

  Measuring section 530 measures the number of terminals 200 connected to each cell of first wireless section 310 and second wireless section 320 from connection information 604 stored in memory 402.

  The adjustment unit 540 calculates the ratio of the number of terminal connections in each cell. The adjusting unit 540 changes the threshold value R for discriminating between a high-speed terminal and a low-speed terminal such that the ratio of the number of connected terminals of each cell becomes the set ratio recorded in the control information 607 of the memory 402.

  A specific example will be described with reference to FIGS.

  Case 1 in FIG. 8 is a comparative example. Case 2 in FIGS. 8 and 9, Case 3 in FIGS. 9 and 10, and Case 4 in FIG. 10 are examples. In each case, the frequency bandwidth per channel is 20 MHz.

  In Case 1, 11ac terminal HT1 of MCS8 and 11ac terminal LT1 of MCS0 are mixed in the cell of frequency f1, and 11ac terminal HT2 of MCS8 and 11ac terminal LT2 of MCS0 are mixed in the cell of frequency f5.

  In the present embodiment, the frequency of 11ac terminal HT2 of MCS8 is changed from frequency f5 to frequency f1, and the frequency of 11ac terminal LT1 of MCS0 is changed from frequency f1 to frequency f5. That is, as in Case 2, 11ac terminals HT1 and HT2 of MCS8 are accommodated in a cell of frequency f1, and 11ac terminals LT1 and LT2 of MCS0 are accommodated in a cell of frequency f5.

  As described above, by controlling the cell of frequency f1 as a high-speed terminal accommodation cell and the cell of frequency f5 as a low-speed terminal accommodation cell, as shown in FIGS. Can be improved.

  When the threshold value R for distributing between the high-speed terminal and the low-speed terminal is fixed, there is a possibility that the number of terminals 200 accommodated in each cell is extremely biased. For example, in case 2, four terminals 200, 11ac terminals HT3 and HT4 of MCS8 and 11ac terminals HT5 and HT6 of MCS4, are newly connected. It is assumed that threshold value R is set to -72 dBm, which is an intermediate value between the reception levels of MCS3 and MCS4. In this case, as in Case 3, the 11ac terminals HT1, HT2, HT3 and HT4 of MCS8 and the 11ac terminals HT5 and HT6 of MCS4 are accommodated in the cell of frequency f1, and the 11ac terminals LT1 and LT1 of MCS0 are accommodated in the cell of frequency f5. LT2 is accommodated.

  In the present embodiment, the threshold value R for distributing high-speed terminals and low-speed terminals is variable, and the threshold value R is adjusted so that the number of terminals in each cell has a set ratio. As an example, it is assumed that the ratio is set to 1: 1 so that the number of terminals is substantially equal in each cell. It is assumed that the threshold value R is changed from -72 dBm, which is the intermediate value between the reception levels of MCS3 and MCS4, to -68 dBm, which is the intermediate value of the reception level between MCS4 and MCS5. In this case, as in Case 4, 11ac terminals HT1, HT2, HT3, and HT4 of MCS8 are accommodated in the cell of frequency f1, and 11ac terminals HT5 and HT6 of MCS4 and 11ac terminals LT1 and LT2 of MCS0 are accommodated in the cell of frequency f5. And are accommodated.

  In this way, by adjusting the number of terminals in each cell to the set ratio, as shown in FIGS. 11, 12, and 13, the terminal 200 accommodated in each cell while suppressing a decrease in system throughput. It is possible to prevent an extreme deviation in the number, and to suppress a decrease in throughput per terminal 200.

*** Explanation of effect of embodiment ***
In the present embodiment, terminal 200 that performs wireless communication via base station 300 is connected to a cell selected according to the length of communication occupation time. Therefore, it is possible to avoid a situation in which a plurality of terminals 200 having greatly different communication occupation times coexist in the same cell. Therefore, according to the present embodiment, it is possible to suppress a decrease in system throughput of wireless communication.

  In the present embodiment, the wireless LAN service area has a dual configuration of an area composed of cells accommodating high-speed terminals having a short communication occupation time and an area composed of cells accommodating low-speed terminals having a long communication occupation time. ing. By selecting and switching the optimal cell according to the reception level of the terminal 200, even when the terminals 200 having different communication occupation times coexist, a decrease in the system throughput can be suppressed. All terminals 200 in the service area can be set as switching targets.

  In the present embodiment, the threshold for distributing high-speed terminals and low-speed terminals is variable. By controlling the threshold value so that the number of terminals in each cell has the set ratio, it is possible to suppress a decrease in throughput per terminal 200 while suppressing a decrease in system throughput.

  In this embodiment, as shown in FIG. 3, the transmission rate is determined based on the reception level and the cell is switched. However, it is necessary to obtain the MCS, the transmission rate, or the frame length information from the header information of the frame. Alternatively, the cell occupation time may be determined by measuring the communication traffic of the transmitted / received data to switch the cell. That is, in the present embodiment, the information on the reception level of the wireless communication performed between base station 300 and terminal 200 is used to determine the length of the communication occupation time. Information on the transmission speed of wireless communication or information on the frame length of wireless communication may be used. That is, in the present embodiment, a cell connecting terminal 200 is selected according to the reception level, but a cell connecting terminal 200 may be selected according to the transmission speed or the frame length.

  In the present embodiment, cell switching within the 802.11ac wireless LAN standard is performed, but cell switching between a plurality of standards such as 802.11n and 802.11a may be performed. In one modification, the terminal 200 supporting the 802.11ac wireless LAN standard capable of high-speed communication is accommodated in a high-speed terminal accommodation cell, and communication at a lower speed than in the 802.11ac wireless LAN standard is performed. The terminal 200 corresponding to the 11a wireless LAN standard is accommodated in the low-speed terminal accommodation cell.

  Although the wireless communication system 100 is a wireless LAN system, the present embodiment can be applied to a wireless communication system other than the wireless LAN system as long as the system performs communication in which a plurality of frame lengths are mixed. it can. That is, the terminal 200 having a short communication occupation time is accommodated in one cell, and the terminal 200 having a long communication occupation time is accommodated in the other cell, thereby suppressing a decrease in system throughput due to a mixture of a plurality of frame lengths. Can be.

  The dual configuration of the cells may be a configuration in which the base station 300 has two radio units as in the present embodiment, or a configuration in which two base stations having one radio unit are installed. The cell configuration is not limited to a double configuration, and may be a triple or higher configuration, and the accommodated cells may be switched according to the communication occupation time within the same system or between different systems. In one modification, the cell configuration is a triple configuration, the high-speed terminal is defined as MCS6 to MCS8, the medium-speed terminal is defined as MCS3 to MCS5, and the low-speed terminal is defined as MCS0 to MCS2. The terminal 200 is accommodated. Alternatively, a high-speed terminal is an 802.11ac wireless LAN-compatible terminal, a medium-speed terminal is an 802.11n wireless LAN-compatible terminal, and a low-speed terminal is an 802.11a wireless LAN-compatible terminal. To accommodate.

In the present embodiment, acquisition section 510 of wireless communication control apparatus 400 acquires a measured value of the reception level of a signal transmitted from terminal 200. The acquisition unit 510 averages the measured values of the reception level during a certain measurement period T, and calculates the average value X _AVE of the reception levels. For the terminal 200 that moves frequently or the terminal 200 in which the surrounding radio propagation environment fluctuates frequently, the reception level, the transmission speed, or the communication occupancy time near the threshold R for discriminating between the high-speed terminal and the low-speed terminal. Fluctuates frequently, and switching of the accommodated cells may occur frequently. When cell switching frequently occurs, a control signal for cell switching is frequently transmitted, and the control signal may lower throughput. Therefore, in the present embodiment, the acquisition interval of the reception level measurement value or the averaging period is lengthened, or the interval of the terminal connection control is made variable, so that the throughput by the control signal for cell switching is reduced. It is possible to suppress the decline.

*** Other configuration ***
In the present embodiment, the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 of the wireless communication control device 400 are realized by software. The functions of the unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 may be realized by dedicated hardware. Alternatively, the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 may be realized by a combination of software and hardware. That is, a part of the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 may be realized by dedicated hardware, and the rest may be realized by software.

  The dedicated hardware is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an FPGA, an ASIC, or a combination of some or all of these. . “IC” is an abbreviation for Integrated Circuit. “GA” is an abbreviation for Gate Array. “FPGA” is an abbreviation for Field-Programmable Gate Array. “ASIC” is an abbreviation for Application Specific Integrated Circuit.

  Both the processor 401 and dedicated hardware are processing circuits. That is, the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 are realized by software, hardware, or a combination of software and hardware. Regardless of this, the operations of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 are performed by the processing circuit.

Embodiment 2 FIG.
This embodiment will be described mainly with reference to FIGS. 14 to 17, which are different from the first embodiment.

*** Configuration description ***
Referring to FIG. 14, the overall configuration of radio communication system 100 according to the present embodiment will be described.

  The entire configuration of the wireless communication system 100 is the same as that of the first embodiment except for the configuration of the terminal accommodation cell switching unit 500 of the wireless communication control device 400. The configuration of the wireless communication control device 400 will be described later.

  FIG. 15 shows an example of the definition of a high-speed terminal and a low-speed terminal.

  In the example of FIG. 15, 20 MHz and 40 MHz can be selected as the wireless communication bandwidth.

  The configuration of wireless communication control apparatus 400 according to the present embodiment will be described with reference to FIG. 14 and FIG.

  The wireless communication control device 400 includes a setting unit 410 and a terminal accommodation cell switching unit 500 as functional elements. The terminal accommodation cell switching unit 500 includes a change unit 550 in addition to the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540. That is, the wireless communication control device 400 corresponding to the connection control device includes the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, the adjustment unit 540, and the change unit 550. The functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, the adjustment unit 540, and the change unit 550 are realized by software.

  In the present embodiment, the wireless communication control program corresponds to the connection control program, and is a program that implements the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, the adjustment unit 540, and the change unit 550. . The wireless communication control program performs processing performed by the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, the adjustment unit 540, and the change unit 550, respectively, as setting processing, acquisition processing, control processing, measurement processing, adjustment processing, and the like. This is a program to be executed by a computer as a change process.

*** Explanation of operation ***
The operation of radio communication system 100 according to the present embodiment will be described mainly with reference to FIG. The operation of wireless communication system 100 corresponds to the wireless communication method according to the present embodiment.

  The processing from step S21 to step S24 is the same as the processing from step S11 to step S14 in the first embodiment, and a description thereof will be omitted.

  In step S25, the changing unit 550 of the wireless communication control device 400 determines that the base station 300 in the cell to which the terminal 200 to which the reception level of the wireless communication is higher than the threshold R among the plurality of cells formed by the base station 300 is connected. The transmission speed per channel in the cell is increased by using the surplus power.

  Specifically, when there is surplus power above the minimum reception level that achieves the highest transmission rate in the high-speed terminal accommodation cell with the SSID “A”, the changing unit 550 uses the surplus power to increase the transmission speed. To shorten the communication occupation time and improve the system throughput. The transmission speed can be increased by the surplus power by any method. In the present embodiment, the transmission speed is increased by increasing the wireless communication bandwidth from 20 MHz to 40 MHz. That is, the change unit 550 determines that the reception level of the 11ac terminal of the MCS8 accommodated in the high-speed terminal accommodation cell is sufficiently higher than the minimum reception level of -59 dBm in the 20 MHz bandwidth and the minimum reception level corresponding to the MCS8 of the 40 MHz bandwidth. It is determined whether there is surplus power enough to satisfy level −56 dBm. Then, when there is such surplus power, the changing unit 550 expands the channel bandwidth from the 20 MHz bandwidth to the 40 MHz bandwidth, and further increases the transmission speed of the terminal 200 accommodated in the high-speed terminal accommodation cell. Do.

  In step S26, the changing unit 550 of the wireless communication control device 400 determines that the base station 300 in the cell to which the terminal 200 whose wireless communication reception level is lower than the threshold R is connected among a plurality of cells formed by the base station 300 and overlapping each other. Increase the transmission power of

  Specifically, the changing unit 550 increases the transmission power of the base station 300 by increasing the transmission power of the base station 300 when there is a terminal 200 having the lowest transmission rate and the minimum reception level in the low-speed terminal accommodation cell with the SSID “B”. Improve and stabilize communication. For example, it is determined whether or not the 11ac terminal of MCS0 whose reception level is equal to or less than the minimum reception level −82 dBm is accommodated in the low-speed terminal accommodation cell. Then, when there is such a terminal 200, changing section 550 increases the transmission power of base station 300 to improve the transmission speed and stabilize the communication in terminal 200 accommodated in the low-speed terminal accommodation cell. By improving the transmission speed, the communication occupation time can be shortened, and by stabilizing the communication, the number of retransmission controls can be reduced, thereby improving the throughput.

  The processing in steps S27 and S28 is the same as the processing in steps S15 and S16 in the first embodiment, respectively, and a description thereof will be omitted.

  The detailed operation of the wireless communication control device 400 will be described. The configuration other than the changing unit 550 is the same as that of the first embodiment, and a description thereof will not be repeated.

  The changing unit 550 increases the transmission speed by expanding the bandwidth from 20 MHz to 40 MHz when there is surplus power from the minimum reception level that realizes the highest transmission speed in the high-speed terminal accommodation cell with the SSID “A”. Do. Cell control for bandwidth expansion is performed for the base station 300 via the output interface 404.

  When there is a terminal 200 having the minimum transmission rate and the minimum reception level in the low-speed terminal accommodation cell having the SSID “B”, the changing unit 550 increases the transmission power of the base station 300 to improve the transmission rate and improve communication. Perform stabilization. Cell control for increasing transmission power is performed on the base station 300 via the output interface 404.

*** Explanation of effect of embodiment ***
In the present embodiment, when the communication status of the terminal 200 accommodated in the high-speed terminal accommodation cell is good, the control by the changing unit 550 can improve the throughput by further increasing the speed.

  In the present embodiment, when the communication status of the terminal 200 accommodated in the low-speed terminal accommodation cell is not good, the control by the changing unit 550 can improve the throughput by stabilizing the communication.

*** Other configuration ***
In the present embodiment, as in Embodiment 1, the functions of setting section 410, acquisition section 510, control section 520, measurement section 530, adjustment section 540, and change section 550 of wireless communication control apparatus 400 are realized by software. However, similarly to the modification of the first embodiment, the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, the adjustment unit 540, and the change unit 550 may be realized by dedicated hardware. . Alternatively, the functions of the setting unit 410, the acquisition unit 510, the control unit 520, the measurement unit 530, the adjustment unit 540, and the change unit 550 may be realized by a combination of software and hardware.

Embodiment 3 FIG.
The present embodiment will be described mainly with reference to FIGS. 18 to 22, which are different from the first embodiment.

*** Configuration description ***
Referring to FIG. 18, the overall configuration of radio communication system 100 according to the present embodiment will be described.

  The overall configuration of the wireless communication system 100 is the same as that of the first embodiment except that the terminal accommodation cell switching unit 500 has moved from the wireless communication control device 400 to the base station 300. In the present embodiment, base station 300 corresponds to a connection control device instead of wireless communication control device 400. The configurations of the wireless communication control device 400 and the base station 300 will be described later.

  The configuration of wireless communication control apparatus 400 according to the present embodiment will be described with reference to FIGS.

  The wireless communication control device 400 includes a setting unit 410 as a functional element. The function of the setting unit 410 is realized by software.

  In the present embodiment, the wireless communication control program is a program that implements the function of setting section 410. The wireless communication control program is a program that causes a computer to execute processing performed by the setting unit 410 as setting processing.

  In the present embodiment, arrangement information 601 and frequency information 602 are stored in memory 402.

  The configuration of base station 300 according to the present embodiment will be described with reference to FIG. 18 and FIG.

  The base station 300 is equipped with a computer such as a microcomputer. The computer of the base station 300 includes a processor 301 and other hardware such as a memory 302, an input interface 303, and an output interface 304. The processor 301 is connected to other hardware via a signal line, and controls the other hardware.

  The base station 300 includes a first wireless unit 310, a second wireless unit 320, and a terminal accommodation cell switching unit 500 as functional elements. The terminal accommodation cell switching unit 500 includes an acquisition unit 510, a control unit 520, a measurement unit 530, and an adjustment unit 540. That is, base station 300 corresponding to the connection control device includes first radio section 310, second radio section 320, acquisition section 510, control section 520, measurement section 530, and adjustment section 540. The functions of the first wireless unit 310, the second wireless unit 320, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 are realized by software.

  The processor 301 is a device that executes a base station program. The base station program corresponds to a connection control program, and is a program that implements the functions of the first wireless unit 310, the second wireless unit 320, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540. The processor 301 is, for example, a CPU, a DSP, or a combination thereof.

  The memory 302 is a device that stores a base station program. The memory 302 is, for example, a RAM, a flash memory, or a combination thereof.

  The input interface 303 is an interface for receiving data input to the base station program. The input interface 303 is, for example, a communication chip or an NIC.

  The output interface 304 is an interface for transmitting data output from the base station program. The output interface 304 is, for example, a communication chip or an NIC.

  Note that the communication interface between the wireless communication control device 400 and the base station 300 may be wired or wireless.

  The base station program is read from the memory 302 to the processor 301 and executed by the processor 301. The memory 302 stores an OS as well as a base station program. The processor 301 executes the base station program while executing the OS. Note that part or all of the base station program may be incorporated in the OS.

  The base station program and the OS may be stored in the auxiliary storage device. The auxiliary storage device is, for example, an HDD, a flash memory, or a combination thereof. The base station program and the OS, when stored in the auxiliary storage device, are loaded into the memory 302 and executed by the processor 301.

  The base station 300 may include a plurality of processors instead of the processor 301. These processors share the execution of the base station program. Each processor is, for example, a CPU, a DSP, or a combination thereof.

  Data, information, signal values, and variable values used, processed, or output by the base station program are stored in the memory 302, the auxiliary storage device, or a register or cache memory in the processor 301.

  In the present embodiment, memory 302 stores cell information 603, connection information 604, speed determination information 605, reception level information 606, and control information 607.

  The base station program executes the processing performed by the first wireless unit 310, the second wireless unit 320, the acquiring unit 510, the control unit 520, the measuring unit 530, and the adjusting unit 540 as a first wireless process, a second wireless process, and an acquiring process, respectively. This is a program to be executed by a computer as control processing, measurement processing, and adjustment processing. The base station program may be provided by being recorded on a computer-readable medium, may be provided by being stored in a recording medium, or may be provided as a program product.

  The base station 300 may include one computer, or may include a plurality of computers. When the base station 300 includes a plurality of computers, the functions of the first wireless unit 310, the second wireless unit 320, the acquiring unit 510, the control unit 520, the measuring unit 530, and the adjusting unit 540 are provided to each computer. It may be realized in a distributed manner.

*** Explanation of operation ***
The operation of radio communication system 100 according to the present embodiment will be described mainly with reference to FIGS. 21 and 22. The operation of wireless communication system 100 corresponds to the wireless communication method according to the present embodiment.

  As compared with Embodiment 1, in the present embodiment, as shown in FIG. 22, signals related to acquisition and averaging of measured values of reception levels, signals related to terminal connection control, and signals related to terminal connection number measurement are wireless. It is transmitted and received not in communication between the communication control device 400 and the base station 300 but in communication within the base station 300. Therefore, the cell switching time between the high-speed terminal accommodation cell and the low-speed terminal accommodation cell can be reduced, and the load on the wireless communication control device 400 can be reduced by reducing the control signals in the wireless communication control device 400.

  The processing in steps S31 and S32 is the same as the processing in steps S11 and S12 in the first embodiment, respectively, and a description thereof will be omitted.

  The processing from step S33 to step S36 is performed in the base station 300 instead of the wireless communication control device 400. Accordingly, communication between the wireless communication control device 400 and the base station 300 is replaced by communication within the base station 300. In other respects, the processing from step S33 to step S36 is the same as the processing from step S13 to step S16 in the first embodiment, and a description thereof will be omitted.

  The detailed operation of the base station 300 will be described.

  For the first wireless section 310 and the second wireless section 320, the frequency is set by the wireless communication control device 400 via the input interface 403.

  Among the first wireless unit 310 and the second wireless unit 320, the first wireless unit 310 sets “SSID” of a cell that accommodates a high-speed terminal whose reception level is higher than the threshold R recorded in the speed determination information 605 of the memory 302 as “ A "is set. The setting is stored in the memory 402 as cell information 603.

  Among the first wireless unit 310 and the second wireless unit 320, the second wireless unit 320 sets “SSID” of a cell that accommodates a low-speed terminal whose reception level is lower than the threshold R recorded in the speed determination information 605 of the memory 302 as “ B ”is set. The setting is stored in the memory 402 as cell information 603.

Acquisition section 510 acquires a measured value of the reception level of a signal transmitted from terminal 200 via input interface 303. The acquisition unit 510 averages the measured values of the reception level during a certain measurement period T, and calculates the average value X _AVE of the reception levels. The average value X _AVE is stored in the memory 302 as reception level information 606.

Based on the reception level information 606 stored in the memory 302, the control unit 520 accommodates the terminal 200 whose reception level is high, that is, _XAVE ≧ R, in the high-speed terminal accommodation cell whose SSID is “A”. Control unit 520 accommodates terminal 200 having a low reception level, that is, _XAVE <R, in a low-speed terminal accommodation cell whose SSID is “B”. Connection control for accommodating each terminal 200 in a cell is performed via the output interface 304. The connection status of each terminal 200 is stored in the memory 302 as connection information 604.

  Measuring section 530 measures the number of terminals 200 connected to each cell of first radio section 310 and second radio section 320 from connection information 604 stored in memory 302.

  The adjustment unit 540 calculates the ratio of the number of terminal connections in each cell. The adjustment unit 540 changes the threshold value R for discriminating between a high-speed terminal and a low-speed terminal such that the ratio of the number of terminal connections in each cell becomes the set ratio recorded in the control information 607 of the memory 302.

*** Explanation of effect of embodiment ***
In the present embodiment, terminal accommodation cell switching section 500 is provided not in radio communication control apparatus 400 but in base station 300, so that the same effect as in Embodiment 1 can be obtained with less control signals and cell switching time. it can.

*** Other configuration ***
In the present embodiment, the functions of first radio section 310, second radio section 320, acquisition section 510, control section 520, measurement section 530, and adjustment section 540 of base station 300 are realized by software. The functions of the first wireless unit 310, the second wireless unit 320, the acquiring unit 510, the control unit 520, the measuring unit 530, and the adjusting unit 540 may be realized by dedicated hardware. Alternatively, the functions of the first wireless unit 310, the second wireless unit 320, the acquiring unit 510, the control unit 520, the measuring unit 530, and the adjusting unit 540 may be realized by a combination of software and hardware. That is, a part of the functions of the first wireless unit 310, the second wireless unit 320, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 is realized by dedicated hardware, and the rest is realized by software. Is also good.

  The dedicated hardware is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an FPGA, an ASIC, or a combination of some or all of these. .

  Both the processor 301 and dedicated hardware are processing circuits. That is, the functions of the first radio unit 310, the second radio unit 320, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 are realized by software, hardware, or both software and hardware. The operation of the first wireless unit 310, the second wireless unit 320, the acquisition unit 510, the control unit 520, the measurement unit 530, and the adjustment unit 540 is performed by a processing circuit, regardless of whether the combination is realized with the hardware.

  Reference Signs List 100 wireless communication system, 200 terminal, 300 base station, 301 processor, 302 memory, 303 input interface, 304 output interface, 310 first wireless section, 320 second wireless section, 400 wireless communication control device, 401 processor, 402 memory, 403 input interface, 404 output interface, 410 setting unit, 500 terminal cell switching unit, 510 acquisition unit, 520 control unit, 530 measurement unit, 540 adjustment unit, 550 change unit, 601 placement information, 602 frequency information, 603 cell information , 604 connection information, 605 speed determination information, 606 reception level information, 607 control information.

Claims (14)

One of a plurality of cells formed by the base station and overlapping each other according to the length of communication occupation time, which is the time during which the wireless communication channel is occupied by a terminal performing wireless communication via the base station. And a control unit that performs control to connect the terminal to the selected cell,
A connection control device comprising: an acquisition unit that acquires information for the terminal to determine the length of the communication occupation time for the terminal.   The connection control device according to claim 1, wherein the information acquired by the acquisition unit includes information indicating a reception level of the wireless communication for the terminal.   The connection control device according to claim 1, wherein the information acquired by the acquisition unit includes information indicating a transmission speed of the wireless communication for the terminal.   The connection control device according to claim 1, wherein the information acquired by the acquisition unit includes information indicating a frame length of the wireless communication for the terminal. A measuring unit for measuring the number of terminals connected to the plurality of cells,
5. The control device according to claim 1, further comprising: an adjustment unit configured to adjust a reference for determining a length of the communication occupation time from information acquired by the acquisition unit in accordance with the number measured by the measurement unit. The connection control device according to any one of the above. The acquisition unit repeatedly acquires the information at a variable frequency,
The control unit, every time the acquisition unit acquires the information, determines the length of the communication occupation time from the information, the cell selected according to the determined length, the terminal is connected The connection control device according to any one of claims 1 to 5, wherein when the terminal is different from the cell, the cell to which the terminal is connected is switched.   A claim, further comprising: a changing unit that increases a transmission rate per channel in the cell using a surplus power of the base station in a cell to which a terminal whose reception level of the wireless communication is higher than a threshold is connected among the plurality of cells. Item 7. The connection control device according to any one of Items 1 to 6.   The radio communication system according to any one of claims 1 to 6, further comprising: a changing unit configured to increase transmission power of the base station in a cell to which a terminal whose reception level of the wireless communication is lower than a threshold is connected among the plurality of cells. Connection control device.   A wireless communication control device, which corresponds to the connection control device according to any one of claims 1 to 8, and sets the plurality of cells to the base station. The base station;
A wireless communication system comprising the wireless communication control device according to claim 9.   A base station that corresponds to the connection control device according to claim 1 and forms the plurality of cells. A base station according to claim 11,
A wireless communication system comprising: a wireless communication control device configured to set the plurality of cells for the base station. The connection control device selects and selects one cell from a plurality of cells formed by the base station and overlapping each other, according to the length of communication occupation time, which is the time during which the wireless communication channel is occupied by the terminal. Perform control to connect the terminal to the cell,
A wireless communication method in which the terminal connects to a cell selected by the connection control device and performs the wireless communication via the base station. On the computer,
One of a plurality of cells formed by the base station and overlapping each other according to the length of communication occupation time, which is the time during which the wireless communication channel is occupied by a terminal performing wireless communication via the base station. And a control process of performing control to connect the terminal to the selected cell,
A connection control program for causing the control process to execute, for the terminal, an acquisition process of acquiring information for determining a length of the communication occupation time.

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