JP5149209B2 - WiMAX base station control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a WiMAX base station control system capable of dispersing a load as an anchor base station. <P>SOLUTION: A WiMAX base station control system 10 has: a mobile terminal 12; a base station 14 connected with the mobile terminal 12 by radio; an EMS 24 connected with the base station 14 via an access network 22 and which controls the base station 14. The base station 14 has a plurality of anchor base stations, each of which serves as a transmission source for packets from the mobile terminal 12 to the access network 22. The EMS 24 collects the number of registration of the mobile terminal 12 registered as the transmission source by each anchor base station, and specifies an anchor base station (14c) with the maximum number of registration which has the maximum collected number of registration, and changes the transmission source of a part of the mobile terminals 12 among the mobile terminals 12 registered to the anchor base station (14c) with the maximum number of registration to the other anchor base station (14a and 14b). Thereby, a load as an anchor base station is dispersed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a WiMAX base station control system including a mobile terminal, a plurality of base stations that are wirelessly connected to the mobile terminal, and an EMS that is connected to the base station via an access network and controls the base station.

  As a next-generation high-speed mobile communication system, WiMAX (Worldwide Interoperability for Microwave Access) has attracted international attention, and the introduction of this system has started.

  FIG. 5 is an explanatory diagram of a general WiMAX communication system. A WiMAX communication system 100 shown in FIG. 5 includes mobile terminals (MS) 12a to 12f, base stations (BS) 102a to 102c, an HA (Home Agent) 16, an AAA server 18, and a Dynamic Host Configuration Protocol (DHCP). A server 20 and an access network 22 are provided.

  The mobile terminals 12a to 12f (hereinafter also referred to as “mobile terminal 12”) are computers or mobile phones having communication functions, and the base stations 102a to 102c (hereinafter also referred to as “base station 102”) are terminals. A wireless device for wireless communication, the mobile terminals 12a and 12b are wirelessly connected to the base station 102a, the mobile terminals 12c and 12d are wirelessly connected to the base station 102b, and the mobile terminals 12e and 12f are wirelessly connected to the base station 102c. Is done. The HA 16 is a server that performs registration and management in which the home address that the mobile terminals 12 a to 12 f have as an identification code and the location information of the mobile terminal 12 are associated, and the DHCP server 20 is a server that assigns an IP address to the mobile terminal 12. It is. The base station 102 is connected to the HA 16, AAA server 18, and DHCP server 20 by an access network 22, and a physical path is formed between the base station 102 and the access network 22.

  For example, in order for the mobile terminal 12a to connect to the Internet, the mobile terminal 12a wirelessly connects to the base station 102a, makes an authentication request to the base station 102a, and when authenticated, individual information is generated and the mobile terminal 12a receives the base station 102a. Registered (network entry). In this case, the base station 102 a that is first registered by the mobile terminal 12 a is an anchor base station (Anchor BS), and serves as a packet transfer start point for the access network 22. When the mobile terminal 12a is registered in the base station 102a, a communication path (data path) is established between the mobile terminal 12a and the access network 22 via the base station 102a.

  Further, the anchor base station of the mobile terminal 12b is the base station 102b. Since the mobile terminal 12b first made a network entry to the base station 102b and then performed a handover to change the wireless connection destination from the base station 102b to the base station 102a, the mobile terminal 12b passed through the base station 102a, the base station 102b, and the access network 22 A communication path is established. In this case, the base station 102a becomes a serving base station (Serving BS) that transfers packets between the mobile terminal 12a and the base station 102b to the mobile terminal 12b. Further, the relationship between the mobile terminals 12c to 12f and the base stations 102b and 102c is that the anchor base station for the mobile terminal 12c is the base station 102b, the anchor base station for the mobile terminal 12d is the base station 102c, and for the mobile terminal 12e. The anchor base station is the base station 102c, and the anchor base station for the mobile terminal 12f is the base station 102c.

  The anchor base station functions not only as a packet transfer starting point between the mobile terminal 12 and the access network 22 but also as an authenticator function related to authentication of the mobile terminal 12, a DHCP relay function that transfers a DHCP message to the DHCP server 20, and the HA 16. It has a function of transferring the transmitted packet to the mobile terminal 12. Also, when the mobile terminal 12 performs a network entry from a base station in the ASN (not shown) to the ASN (R3 handover) or when the mobile terminal 12 starts up and enters the network in the ASN. In addition, the base station 102 with network entry becomes an anchor base station. In FIG. 5, since the base stations 102a to 102c form the same ASN (Access Service Network), the anchor base station is not changed even if the mobile terminal 12 is handed over in this ASN.

WiMAX FORUM “WiMAX Forum Network Architecture” March 28, 2007 p.151-p. 191

  However, in the base station 102 shown in FIG. 5, the number of mobile terminals registered with the base station 102a as the anchor base station is one of the mobile terminals 12a, and the number of registrations with the base station 102b as the anchor base station is the mobile terminal 12b. , 12c, and the number of mobile terminals having the base station 102c as an anchor base station is three mobile terminals 12d to 12f. Therefore, since the number of mobile terminals having the base station 102c as an anchor base station is the largest, the load is larger than other base stations. Further, when the load is concentrated on a specific base station and the base station fails, the influence on the entire system is great.

  The present invention has been made in consideration of the above problems, and an object thereof is to provide a WiMAX base station control system capable of distributing the load as an anchor base station.

  A WiMAX base station control system according to the present invention includes a mobile terminal, a plurality of base stations that are wirelessly connected to the mobile terminal, and an EMS that is connected to the base station via an access network and controls the base station. In the WiMAX base station control system, the plurality of base stations include a plurality of anchor base stations serving as transfer points of packets from the mobile terminal to the access network, and the EMS includes the anchor base stations from the anchor base stations. Collecting the number of registrations of the mobile terminal registered as a transfer origin, identifying the maximum number of registered anchor base stations where the collected number of registrations is the maximum, and the movement registered in the maximum number of registered anchor base stations In the terminal, the transfer starting point of some of the mobile terminals is changed to another anchor base station.

  In addition, the EMS identifies the registration number minimum anchor base station with the collected minimum number of registrations, and changes the transfer start point of the mobile terminal from the registration number maximum anchor base station to the registration number minimum anchor base station. Then, the difference between the registered number registered in the maximum registered anchor base station after the change and the registered number registered in the minimum registered anchor base station after the change is 1 or less. To.

  According to the present invention, the EMS of the WiMAX base station control system collects the number of registrations of the mobile terminal registered as the transfer origin from each anchor base station, and the number of registrations collected is the maximum. By identifying the maximum anchor base station and changing the transfer start point of some of the mobile terminals to the other anchor base stations among the mobile terminals registered in the maximum number of registered anchor base stations, The load as a station can be distributed.

It is explanatory drawing of a structure of the WiMAX base station control system which concerns on embodiment of this invention. It is explanatory drawing of the process sequence of the load distribution of an anchor base station. It is explanatory drawing of the structure of the communication path after the load distribution process of an anchor base station. It is explanatory drawing of the other structure of the communication path after the load distribution process of an anchor base station. It is explanatory drawing of the conventional general WiMAX communication system.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of a configuration of a WiMAX base station control system 10 according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of an anchor base station load distribution processing procedure in the WiMAX base station control system 10. FIG. 3 is an explanatory diagram of the configuration of the communication path after the load distribution process of the anchor base station, and FIG. 4 is an explanatory diagram of another configuration of the communication path after the load distribution process of the anchor base station.

  In the WiMAX base station control system 10 shown in FIG. 1, the base stations 102a to 102c in the WiMAX communication system 100 shown in FIG. 5 are respectively replaced with base stations 14a to 14c (hereinafter also referred to as “base station 14”). An EMS (Element Management System) 24 that distributes and controls the load of the base station 14 serving as the anchor base station is provided.

  Next, load distribution control of the base station 14 serving as an anchor base station by the EMS 24 will be described with reference to FIGS.

  First, the EMS 24 collects information regarding the base stations 14a to 14c (step S1). Specifically, the EMS 24 transmits a message “SNMP-GetRequest” to the base stations 14a to 14c, and receives a response message “SNMP-GetResponse” from the base stations 14a to 14c. The EMS 24 specifies the mobile terminal 12 to be an anchor base station for each base station of the base stations 14a to 14c from the response message “SNMP-GetResponse”, and is registered as an anchor base station for each base station 14a to 14c. The registered number Xn of the mobile terminal 12 is acquired. In FIG. 1, since it is the mobile terminal 12a that uses the base station 14a as the anchor base station, Xa = 1, and since the base station 14b that uses the anchor base station is the mobile terminals 12b and 12c, Xb = 2 Since the mobile terminals 12d, 12e, and 12f use the base station 14c as the anchor base station, Xc = 3.

  Next, the EMS 24 identifies the base station with the maximum number of registrations Xn as the registration number maximum anchor base station and the minimum base station as the registration number minimum anchor base station (step S2), and the registration number of the registration number maximum anchor base station. Is the maximum registration number Nmax, and the registration number of the minimum anchor base station is the minimum registration number Nmin. In FIG. 1, the maximum anchor base station is the base station 14c and the maximum registration number Nmax = 3, and the minimum anchor base station is the base station 14a and the minimum registration number Nmin = 1.

  The EMS 24 determines an appropriate distribution number of the registration number of the mobile terminal 12 in the anchor base station based on the acquired registration number Xn (step S3). Specifically, a difference between a numerical value Nmax ′ obtained by subtracting 1 from the maximum registered number Nmax and a numerical value Nmin ′ obtained by adding 1 to the minimum registered number Nmin is obtained. This process corresponds to changing the anchor base station of the mobile terminal 12 from the maximum anchor base station to the minimum anchor base station, and the EMS 24 changes the anchor base station before and after the change and the mobile terminal 12 to be changed. Obtained as anchor base station change information.

  When the difference does not become 1 or less, the numerical value Nmax ′ and the numerical value Nmin ′ are compared with the registration number Xn of the base station other than the maximum anchor base station and the minimum anchor base station, and the new maximum registration number Nmax and the minimum registration number are newly compared. Nmin is obtained. When the difference between the newly obtained maximum number Nmax 'obtained by subtracting 1 from the maximum registration number Nmax' and the newly obtained minimum number of registrations Nmin obtained by adding 1 to the number Nmin 'is obtained, and the difference does not become 1 or less Until the difference becomes 1 or less, the above-described procedure in the case where the difference does not become 1 or less is repeated. In FIG. 1, the maximum anchor base station is the base station 14c, the maximum registration number Nmax = 3, the minimum anchor base station is the base station 14a, the minimum registration number Nmin = 1, and 1 is subtracted from the maximum registration number Nmax. 2. When 1 is added to the minimum registration number Nmin, it becomes 2, the difference becomes 0, and the difference becomes 1 or less.

  Next, when the difference becomes 1 or less, the EMS 24 sends a message “to the base station 14a that is the anchor base station after the change that has become the anchor base station of the mobile terminal 12e based on the anchor base station change information”. SNMP-SetRequest ”is transmitted to notify that the mobile terminal 12 to be changed is an anchor base station (step S4).

  Further, an R4 path (GRE tunnel) is generated between the anchor base stations before and after the change, that is, between the base station 14a and the base station 14c (step S5).

  The base station 14a, which is the anchor base station after the change, performs MIP registration processing on the HA 16, and the HA 16 performs authentication processing on the mobile terminal 12e whose anchor base station has been changed on the AAA server 18 (step) S6). As a result, a communication path is established between the mobile terminal 12e and the access network 22 via the base stations 14c and 14a.

  The base station 14a transmits the message “SNMP-GetResponse” to the EMS 24 after the anchor base station destination of the mobile terminal 12e is changed from the base station 14c to the base station 14a, and the anchor base station distributed processing is completed. (Step S7). As a result, the registered numbers Xn of the base stations 14a, 14b, and 14c are all equalized to two, and the load is distributed.

  In step S3, among the mobile terminals 12d, 12e, and 12f having the base station 14c that is the maximum number of registered anchor base stations as an anchor base station, the anchor base station of the mobile terminal 12e is used to reduce the load on the base station 14c. Is changed from the base station 14c to the base station 14a. In order to reduce the load on the base station 14c, the anchor base station of the mobile terminal 12d may be changed from the base station 14c to the base station 14a. In such a case, after deleting the R4 path generated between the base station 14b and the base station 14c, an R4 path is generated between the base station 14a and the base station 14b (see FIG. 4). As a result, a communication path is established between the mobile terminal 12d and the access network 22 via the base stations 14b and 14a.

  Furthermore, in step S3, as long as the load distribution as the anchor base station can be achieved, the load distribution method is not limited to the method of setting the difference between the maximum registration number Nmax and the minimum registration number Nmin to 1 or less. . For example, the average number of registrations is calculated from each registered number Xn of the base stations 14a, 14b, and 14c, and the anchor base stations that are equal to or greater than the average number of registrations and the anchor base stations that are equal to or less than the average number of registrations are identified By distributing the number of registrations, which is the difference between the number of registered anchor base stations Xn and the average number of registrations, to anchor base stations having an average number of registrations or less, the load distribution as the anchor base stations may be distributed. At this time, if the difference registration number matches the difference registration number between the average registration number and the registration number Xn of the anchor base station equal to or less than the average registration number, the anchor base station of the mobile terminal 12 between the anchor base stations. You may change stations.

  As described above, the WiMAX base station control system 10 controls the base station 14 by connecting to the mobile terminal 12, the base station 14 wirelessly connected to the mobile terminal 12, and the base station 14 via the access network 22. The base station 14 has a plurality of anchor base stations that serve as transfer starting points for packets from the mobile terminal 12 to the access network 22, and the EMS 24 is registered as the transfer starting point from each anchor base station. The number of registrations of the mobile terminal 12 is collected, the registration number maximum anchor base station (14c) whose collected number is the maximum is specified, and the mobile terminal 12 registered in the registration number maximum anchor base station (14c) Among them, the transfer starting point of some mobile terminals 12 is changed to another anchor base station (14a, 14b). Thereby, the load as an anchor base station can be distributed.

  In addition, the EMS 24 identifies the registered number minimum anchor base station (14a) having the collected minimum number of registrations, and moves from the registered number maximum anchor base station (14c) to the registered number minimum anchor base station (14a). The transfer start point of the terminal 12 is changed, and the registered number registered in the registered maximum anchor base station (14c) after the change and the registered minimum anchor base station (14a) after the change are registered. The difference from the registered number is 1 or less.

  The present invention is not limited to the above-described embodiment, and it goes without saying that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... WiMAX base station control system 12, 12a-12f ... Mobile terminal 14, 14a-14c, 102, 102a-102c ... Base station 16 ... HA 18 ... AAA server 20 ... DHCP server 22 ... Access network 24 ... EMS 100 ... WiMAX Communications system

Claims (2)

A WiMAX base station control system comprising: a mobile terminal; a plurality of base stations that are wirelessly connected to the mobile terminal; and an EMS that is connected to the base station via an access network and controls the base station,
The plurality of base stations have a plurality of anchor base stations serving as transfer points of packets from the mobile terminal to the access network,
The EMS is
Collect the registration number of the mobile terminal registered as the transfer origin from each anchor base station,
Identify the maximum number of registered anchor base stations for which the collected number of registrations is the maximum,
The WiMAX base station control system, wherein, among the mobile terminals registered in the maximum number of registered anchor base stations, the transfer starting point of some of the mobile terminals is changed to another anchor base station. In the WiMAX base station control system according to claim 1,
The EMS is
Identify the minimum number of registered anchor base stations for which the collected number of registrations is minimum;
The transfer start point of the mobile terminal is changed from the registered maximum anchor base station to the registered minimum anchor base station, the registered number registered in the registered maximum anchor base station after the change, and the changed The WiMAX base station control system is characterized in that a difference between the registered number and the registered number registered in the minimum anchor base station is 1 or less.

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