JP2011120133A - Base station device, scheduling apparatus, control apparatus, control method of base station, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve response capability to the rapid variation of traffic depending upon the place, where a base station is installed, in the base station capable of performing radio communication with a plurality of mobile stations using a plurality of frequency channels. <P>SOLUTION: A base station 1 includes a radio communication unit 10 and a control unit 11. The radio communication unit 10 is configured to perform radio communication with a plurality of mobile stations using a plurality of frequency channels. The control unit 11 controls the frequency channel, that the radio communication unit 10 uses, based on a schedule in which the channel or the number of channels to be used for the radio communication with a mobile station is determined among the plurality of frequency channels, wherein the schedule is created based on past periodic traffic characteristics in the radio communication unit 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels.

  In a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels, there is a technique for changing the number of frequency channels used for communication with a mobile station according to an increase or decrease in traffic. Known (see Patent Documents 1 and 2). The term “frequency channel” used in this specification means a unit of bandwidth (frequency resource) allocated to a base station. For example, in UTRAN (UMTS Terrestrial Radio Access Network) / W-CDMA (Wideband Code division Multiple Access), one frequency channel has a bandwidth of 5 MHz. In E-UTRAN (Evolved UTRAN) / LTE (Long Term Evolution), one frequency channel has a bandwidth of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz.

  Patent Document 1 discloses a base station that can perform wireless communication with a plurality of mobile stations using a plurality of frequency channels. The base station disclosed in Patent Document 1 increases or decreases the number used for communication with a mobile station among a plurality of frequency channels in accordance with increase or decrease of traffic of the base station. For example, the base station disclosed in Patent Document 1 communicates with a plurality of mobile stations using only one frequency channel when traffic is low, and uses two frequency channels when traffic increases. Communicate with multiple mobile stations. Thereby, the base station disclosed in Patent Document 1 can reduce power consumption when traffic is low.

  Patent Document 2 discloses a base station having a group configuration including a master base station and a slave base station. The base station disclosed in Patent Literature 2 normally operates only the master base station to communicate with the mobile station, and sets the slave base station in a standby state. And the base station apparatus disclosed by patent document 2 makes a slave base station an operation state additionally according to detecting the increase in traffic. The base station apparatus disclosed in Patent Document 2 can reduce power consumption by stopping transmission of a slave base station when traffic is low.

  Patent Document 3 discloses a wireless communication terminal that supports a plurality of wireless communication standards such as WiMAX (Worldwide Interoperability for Microwave Access) and wireless LAN (Local Access Network). For example, when wireless transmission by WiMAX and wireless transmission by wireless LAN occur at the same time, the wireless communication terminal of Patent Literature 3 preferentially executes transmission by WiMAX and schedules transmission to interrupt transmission by wireless LAN. I do. The wireless communication terminal of Patent Document 3 shares one wireless transmission circuit for transmission using a plurality of wireless communication standards (for example, WiMAX and wireless LAN), and performs the above-described transmission scheduling, thereby reducing the circuit scale and power consumption. Can be reduced.

  Patent Document 4 discloses a cellular communication system in which transmission power of a plurality of base stations arranged adjacent to each other is relatively changed according to a traffic state. Specifically, when the traffic of one base station increases, the transmission power of the one base station is reduced to reduce the coverage area (cell) of the base station and the transmission of the other adjacent base station Increase the power to increase the coverage area (cell) of the other base station. Thereby, when a track | truck concentrates in one base station (cell), traffic can be disperse | distributed between adjacent base stations.

JP 2000-269746 A JP 2005-354549 A JP 2009-111630 A JP 2001-160984 A

  As described above, Patent Documents 1 and 2 disclose techniques for dynamically changing a frequency channel used by a base station in response to an increase or decrease in traffic. However, the techniques disclosed in Patent Documents 1 and 2 may not be able to sufficiently follow the rapid fluctuation of traffic depending on the location of the base station.

  The traffic to be processed by the base station may increase rapidly concentrating on a specific time. In addition, the traffic fluctuation characteristics vary depending on the location of the base station (commercial or residential area, etc.). For example, in commercial areas, particularly office areas, traffic tends to increase sharply around the start time of weekdays and after noon. As disclosed in Patent Documents 1 and 2, the control for increasing the number of frequency channels after detecting an increase in traffic may not be in time for the rapid increase in traffic. This is because it takes time until an additional frequency channel can be used. Therefore, there is a concern that some mobile stations may temporarily be unable to communicate, or that there may be mobile stations that cannot be assigned a desired communication band due to insufficient bandwidth.

  Patent Documents 3 and 4 disclose a technique for enabling a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels to cope with a sudden increase in traffic. Not done.

  The present invention was made on the basis of the above-mentioned knowledge by the inventors of the present application, and in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels, The purpose is to improve the ability to cope with rapid fluctuations in traffic depending on the location of the base station.

  The base station apparatus according to the first aspect of the present invention includes a radio communication unit and a control unit. The wireless communication unit is configured to perform wireless communication with a plurality of mobile stations using a plurality of frequency channels. The control unit controls a frequency channel used by the wireless communication unit based on a schedule that defines a channel or the number of channels used for the wireless communication among the plurality of frequency channels. Here, the schedule is created based on past periodic traffic characteristics in the wireless communication unit.

  The scheduling apparatus according to the second aspect of the present invention includes a traffic management unit and a schedule generation unit. The traffic management unit sequentially collects the traffic generation status in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels in a time series, and By collecting the traffic generation information of the series, the past periodic traffic characteristics in the base station are generated. In addition, the schedule generation unit creates a schedule in which a channel or the number of channels to be used for the wireless communication among the plurality of frequency channels is determined based on the periodic traffic characteristics.

  The control apparatus according to the third aspect of the present invention is based on past periodic traffic characteristics in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels. A control unit that controls a frequency channel used by the base station based on a schedule that is created and defines a channel or the number of channels used for the wireless communication among the plurality of frequency channels.

  A 4th aspect of this invention is related with the control method of a base station. The method is created based on a past periodic traffic characteristic in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels. The method includes controlling a frequency channel used by the base station based on a schedule that defines a channel or the number of channels used for the wireless communication.

  A 5th aspect of this invention is related with the program for making a computer perform the control method regarding the base station which can perform radio | wireless communication between several mobile stations using several frequency channels. The control method performed by a computer that executes the program is based on past periodic traffic characteristics in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels. The frequency channel used by the base station is controlled based on a schedule that defines the channel or number of channels used for the wireless communication among the plurality of frequency channels.

  According to each aspect of the present invention described above, a base station apparatus, a scheduling apparatus, a control apparatus, and a base station that can contribute to an improvement in the ability to cope with a rapid change in traffic depending on the installation location of the base station. A control method and a program can be provided.

It is a block diagram which shows the structural example of the base station concerning Embodiment 1 of invention. It is a block diagram which shows the structural example of the control part shown in FIG. It is a figure which shows the structural example of a traffic data management table. It is a figure which shows an example of a specific traffic statistic. It is a figure which shows an example of the usage schedule of RF channel. It is a figure which shows an example of ON / OFF instruction | indication of RF channel. It is a block diagram which shows the structural example of the control part which the base station concerning Embodiment 2 of invention has. It is a flowchart which shows the specific example of ON / OFF control of RF channel in the base station concerning Embodiment 2 of invention.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary for the sake of clarity.

<Embodiment 1 of the Invention>
The base station 1 according to the present embodiment is configured to be able to perform wireless communication with a plurality of mobile stations using a plurality of frequency channels (hereinafter referred to as RF channels). Furthermore, the base station 1 according to the present embodiment selects a frequency channel to be used for radio communication based on an RF channel schedule that defines a channel to be used for radio communication with a mobile station or the number of channels among a plurality of frequency channels. decide.

  Here, the RF channel schedule is created based on past periodic traffic characteristics. Periodic means a 5-minute period, an hour period, a daily period, a week period, an annual period, and the like. For example, statistics that can estimate the amount of traffic that occurs periodically in a specific time period by aggregating traffic data for a specific time period (for example, 9 am to 9:05 am on Monday) over a plurality of weeks (For example, moving average) may be calculated. This statistic corresponds to “past periodic traffic characteristics”. Then, an RF channel or the number of channels necessary to accommodate the traffic amount grasped from the obtained statistics is determined, and an RF channel schedule may be created. It should be noted that the calculation of the past periodic traffic characteristics and the determination of the RF channel schedule may be performed by the base station 1 or in a higher level network (such as a cellular communication company's core network) to which the base station 1 is connected. It may be performed by a deployed device.

  As described above, the traffic to be processed by the base station 1 may increase rapidly while concentrating on a specific time. In addition, the traffic fluctuation characteristics may vary depending on the installation location of the base station 1 (whether it is a commercial area or a residential area). The base station 1 according to the present embodiment can change the number of RF channels used for communication with a mobile station based on an RF channel schedule reflecting periodic traffic characteristics unique to the installation location of the base station 1. That is, if it can be understood that traffic rapidly increases in a specific time zone based on past periodic traffic characteristics, the number of RF channels used in that time zone can be increased in advance. On the other hand, if a time zone with a small traffic volume can be grasped based on the past periodic traffic characteristics, the number of RF channels used in that time zone can be reduced in advance. Therefore, according to the present embodiment, it is possible to improve the ability to cope with a sudden change in traffic depending on the installation location of the base station 1 while reducing the power consumption.

  Below, the structural example of the base station 1 and the specific example of operation | movement are demonstrated in detail. Here, an example will be described in which the base station 1 itself performs traffic monitoring, calculation of past periodic traffic characteristics, and generation of an RF channel schedule. FIG. 1 is a block diagram illustrating a configuration example of the base station 1. In FIG. 1, a wireless communication unit 10 performs bidirectional wireless communication with a plurality of mobile stations using an antenna 100. The radio communication unit 10 transmits a downlink radio signal encoded with control data and user data to each mobile station, and receives an uplink radio signal transmitted from each mobile station. The radio communication unit 10 decodes received data from the uplink radio signal.

  The control unit 11 monitors traffic generated between the radio communication unit 10 and the mobile station, calculates past periodic traffic characteristics, and generates an RF channel schedule. In addition, the control unit 11 instructs the radio communication unit 10 on usable RF channels according to the RF channel schedule.

  A configuration example of the control unit 11 is shown in FIG. In FIG. 2, the traffic management unit 110 monitors the traffic generation status in the cell generated by the base station 1 and sequentially collects traffic data indicating the traffic volume at regular time intervals in time series. The traffic to be monitored may be downlink traffic transmitted from the base station 1 to the mobile station in the cell, uplink traffic transmitted from the mobile station to the base station 1, or both. The traffic monitoring may be performed by monitoring at least one parameter having a correlation with the traffic volume. Parameters having a correlation with the traffic volume include, for example, transmission data volume, received data volume, downlink transmission power in the RF channel, uplink total received power (RTWP: Received Total Wideband Power) from a plurality of mobile stations, RF channel The number of subcarriers used, the subcarrier usage rate, and the like.

  Furthermore, the traffic management unit 110 calculates the periodic traffic characteristics of the base station 1 using the traffic data collected sequentially. In the example of FIG. 2, the periodic traffic characteristics of the base station 1 are managed using the traffic data management table 111. The management table 111 may hold, for example, periodic traffic statistics such as every time zone, every day of the week, and every attribute (weekdays, weekends and holidays, daytime, nighttime, etc.). The traffic statistics may be a moving average for a predetermined period, for example. For example, the moving average of the past 10 weeks may be calculated for the traffic volume for each day of the week and every 5 minutes, and this may be stored in the traffic data management table 111 as traffic statistics.

  FIG. 3 is a diagram illustrating an example of the traffic data management table 111. In the example of FIG. 3, the traffic data management table 111 holds a moving average (average traffic) for a predetermined period for each attribute (whether weekdays, weekends, and holidays), for each day of the week, and for every five minutes.

  The schedule generation unit 112 generates an RF channel schedule based on the periodic traffic characteristics of the base station 1 collected by the traffic management unit 110. More specifically, the schedule generation unit 112 may specify at least one of an attribute, a day of the week, and a time zone and request the traffic management unit 110 to transmit a specific traffic statistic. The traffic management unit 110 may acquire the traffic statistics for the attribute, day of the week, and time period specified by the schedule generation unit 112 from the table 111 and transmit them to the schedule generation unit 112. And the schedule production | generation part 112 should just determine RF channel or the number of channels which should be used in the specific time slot | zone based on the traffic statistic of the acquired specific time slot | zone.

  FIG. 4 shows an example of traffic statistics for a specific time period supplied from the traffic management unit 110 to the schedule generation unit 112. In the example of FIG. 4, the average traffic of all the time zones every 5 minutes on Monday is transmitted.

  FIG. 5 shows an example of an RF channel schedule created by the schedule generation unit 112 in accordance with the traffic statistics shown in FIG. The traffic statistics shown in FIG. 4 indicate that traffic suddenly increases between 9:00 am and 9:05 am on Monday. Therefore, in the example of FIG. 5, one RF channel (RF1) is used between 8:55 am and 9:00 am on Monday, and two between 9:00 am and 9:05 am on Monday. It has been decided to use RF channels (RF1 and RF2). Note that, when the base station 1 employs a sector configuration and a plurality of antennas 100 associated with each sector are arranged, the schedule generation unit 112 may generate an RF channel schedule for each antenna 100. .

  Returning to FIG. The radio resource control unit 113 illustrated in FIG. 2 instructs the radio communication unit 10 to turn on / off the RF channel according to the RF channel schedule. FIG. 6 shows an example of RF channel setting on Mondays from 9:00 am to 9:05 instructed to the wireless communication unit 10 according to the schedule of FIG.

  Upon receiving the ON / OFF instruction from the radio resource control unit 113, the radio communication unit 10 determines the operational state of amplifiers (not shown) necessary for using each RF channel in accordance with the instruction from the radio resource control unit 113. Change it. That is, the radio communication unit 10 may put an amplifier or the like related to an unused RF channel into a dormant state with low power consumption. In addition, the wireless communication unit 10 may complete the activation operation in advance prior to arrival of the instructed time zone so that the RF channel instructed to be ON can be used immediately in the instructed time zone.

  According to the specific examples described with reference to FIGS. 2 to 7, scheduling related to use of the RF channel of the base station 1 is automatically performed by reflecting periodic traffic characteristics peculiar to the installation location of the base station 1. Can do. In other words, the specific example of the base station 1 described with reference to FIG. 2 to FIG. 7 learns traffic characteristics at its installation location, predicts future traffic generation, and prepares to use the RF channel efficiently. be able to.

  The operations and functions performed by the traffic management unit 110, the management table 111, the schedule generation unit 112, and the radio resource control unit 113 illustrated in FIG. 2 do not necessarily have to be arranged in the base station 1. The arrangement of these functions and operations is appropriately determined according to the design concept of the network architecture. Therefore, at least a part of these functions and operations may be arranged in an upper network (not shown) connected to the base station 1.

  Also, at least some of the operations and functions performed by the traffic management unit 110, the management table 111, the schedule generation unit 112, and the radio resource control unit 113 shown in FIG. 2 are ASIC (Application Specific Integrated Circuit), DSP ( You may implement | achieve using the computer system containing a digital signal processor (MPU), micro processing unit (MPU) or CPU (Central Processing Unit), or these combination. Specifically, one or more programs including a group of instructions for causing a computer to perform these operations and functions may be executed by a computer system. Note that these programs can be stored in various types of storage media accessible by the computer system. In addition, these programs can be transmitted via a communication medium. Here, the storage medium includes, for example, a flexible disk, a hard disk, a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD, a ROM cartridge, a battery-backed RAM memory cartridge, a flash memory cartridge, a nonvolatile RAM cartridge, and the like. . In addition, the communication medium includes a wired communication medium such as a telephone line, a wireless communication medium such as a microwave line, and the Internet.

<Embodiment 2 of the Invention>
In the present embodiment, an example will be described in which the RF channel is switched ON / OFF in real time in accordance with the current traffic generation status in addition to scheduling of the used RF channel based on the past periodic traffic characteristics. The overall configuration of the base station according to the present embodiment may be the same as the configuration shown in FIG. FIG. 7 is a block diagram illustrating a configuration example of the control unit 11 included in the base station according to the present embodiment. Operations of the traffic management unit 110, the management table 111, and the schedule generation unit 112 illustrated in FIG. 7 may be the same as those of the elements having the same reference numerals illustrated in FIG.

  The radio resource control unit 213 in FIG. 7 instructs the radio communication unit 10 to turn on / off the RF channel based on the RF channel schedule, similarly to the radio resource control unit 113 in FIG. Furthermore, the radio resource control unit 213 instructs the radio communication unit 10 to turn on / off the RF channel in real time according to the current traffic generation state. Specifically, when it is determined that the current traffic cannot be processed with the number of RF channels determined based on the RF channel schedule, the radio resource control unit 213 turns on the additional RF channel. 10 may be indicated.

  FIG. 8 is a flowchart showing a specific example of the operation of the radio resource control unit 213. In step S801, the radio resource control unit 213 acquires the latest traffic data. This traffic data may be a measurement result of traffic generated in the immediately preceding predetermined period. In step S802, the radio resource control unit 213 determines whether the current number of RF channels is appropriate in light of the latest traffic amount grasped from the acquired traffic data.

  If the current number of RF channels is appropriate (YES in step S802), the radio resource control unit 213 proceeds to a waiting process for a predetermined time (step S804). On the other hand, if it is determined that the current number of RF channels is inappropriate (NO in step S802), the radio resource control unit 213 derives the necessary number of RF channels and instructs the radio communication unit 10 to turn on the additional RF channel. Instruct. In step S804, the radio resource control unit 213 monitors the elapse of a certain time, and executes step S801 again when the certain time elapses. The fixed time in step S804 may be appropriately determined in accordance with the traffic data acquisition cycle.

  According to the present embodiment, it is possible to cope with a sudden increase in traffic that is not reflected in the RF channel schedule. In addition, when the radio resource control unit 213 determines to continue the traffic situation that can be handled with a smaller number of channels than the number of RF channels in use based on the RF channel schedule, the radio resource control unit 213 turns off some of the RF channels and uses The number of RF channels may be reduced. Thereby, the power consumption of the base station can be further reduced.

  Note that the operations and functions performed by the traffic management unit 110, the management table 111, the schedule generation unit 112, and the radio resource control unit 213 illustrated in FIG. 7 do not necessarily have to be arranged in the base station 1. The arrangement of these functions and operations is appropriately determined according to the design concept of the network architecture. Therefore, at least a part of these functions and operations may be arranged in an upper network (not shown) connected to the base station 1.

  Further, at least a part of the operations and functions performed by the control unit 11 illustrated in FIG. 7 may be realized by causing a computer system to execute a program.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention described above.

DESCRIPTION OF SYMBOLS 1 Base station 10 Wireless communication part 11 Control part 100 Antenna 110 Traffic management part 111 Traffic data management table 112 Schedule production | generation part 113, 213 Radio | wireless resource control part

Claims (10)

A wireless communication unit capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels;
Created based on past periodic traffic characteristics in the wireless communication unit and used by the wireless communication unit based on a schedule that defines a channel or number of channels to be used for the wireless communication among the plurality of frequency channels A control unit for controlling the frequency channel;
A base station apparatus comprising:   The base station apparatus according to claim 1, wherein, in addition to the control based on the schedule, the control unit increases a radio frequency usable by the radio communication unit according to an increase in current traffic in the radio communication unit. .   The base station apparatus according to claim 1, wherein the periodic traffic characteristics include a traffic generation history for each time zone, a traffic generation history for each day of the week, a traffic generation history for weekdays, and a traffic generation history for weekends and holidays. .   The base station apparatus of any one of Claims 1-3 further provided with the schedule production | generation part which produces | generates the said schedule based on the said periodic traffic characteristic.   The traffic management part which collects the traffic generation situation of the radio communication part sequentially along a time series, and generates the periodic traffic characteristic by totaling the collected time series traffic generation information, further comprising: The base station apparatus of any one of 1-4. Collect the traffic generation status of base stations that can communicate wirelessly with multiple mobile stations using multiple frequency channels in time series, and collect the time-series traffic generation information collected. A traffic management unit for generating past periodic traffic characteristics in the base station by counting, and
A schedule generation unit that creates a schedule that defines a channel or the number of channels to be used for the wireless communication among the plurality of frequency channels based on the periodic traffic characteristics;
A scheduling apparatus comprising: Created based on past periodic traffic characteristics in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels, and the wireless communication among the plurality of frequency channels A control unit that controls a frequency channel used by the base station based on a schedule that defines a channel or the number of channels to be used for
Control device.   The control device according to claim 7, wherein the control unit increases a radio frequency usable by the base station according to an increase in current traffic in the base station, in addition to the control based on the schedule. Created based on past periodic traffic characteristics in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels, and the wireless communication among the plurality of frequency channels Control the frequency channel used by the base station based on a schedule that defines the channel or number of channels used for
Base station control method. A program for causing a computer to perform a control method related to a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels,
The control method is:
Created based on past periodic traffic characteristics in a base station capable of performing wireless communication with a plurality of mobile stations using a plurality of frequency channels, and the wireless communication among the plurality of frequency channels Controlling the frequency channel used by the base station based on a schedule defining the channel or number of channels used for
Including the program.

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