KR20100078204A - Mobile telecommunication system and method for balancing load - Google Patents

Abstract

PURPOSE: A mobile communication system for balancing a load and a method thereof are provided to distribute a load for UE mobility management of an MME not to automatically select the specific MME, thereby increasing stability and reliability of the system. CONSTITUTION: A load balancing mobile communication system comprises a plurality of MMEs(Mobility Management Entities)(30) and an eNB(E-UTRAN NodeB)(20). The plurality of MMEs forms load balancing control information. The plurality of MMEs transmits the load balancing control information. The eNB stores the load balancing control information. If a specific UE(User Device)(10) is connected, the eNB selects the MME with the least load using the load balancing control information.

Description

Load balancing mobile communication system and method {MOBILE TELECOMMUNICATION SYSTEM AND METHOD FOR BALANCING LOAD}

The present invention relates to a mobile communication system and method, and more particularly, to a method and a mobile communication system capable of preventing load concentration when selecting a MME (Mobility Management Entity) in charge of terminal mobility management in a base station node.

Global System for Mobile Communications (GSM) or Interim Standard (IS) -95 is a second generation mobile communication method that provides voice-oriented services. GSM, a Time Division Multiple Access (TDMA) scheme, was commercialized around Europe in 1992, and IS-95, a Code Division Multiple Access (CDMA) scheme, is Korea. And in the United States.

Recently, a mobile communication system has evolved from a voice-oriented service to a high-speed, high-quality third generation mobile communication system for providing data and multimedia services. The third generation mobile communication system uses a CDMA scheme, and is based on the 3rd Generation Partnership Project (3GPP) and the 3rd Generation Partnership Project (3GPP2) based on the synchronization between the base stations based on the asynchronous between the Node Bs, or CDMA2000. ). 3GPP, also called Universal Mobile Telecommunications System (UMTS), is a European standard, and 3GPP2, also called CDMA2000, is an American standard.

Long Term Evolution (LTE) system is an evolution from the existing UMTS system and is currently being standardized in 3GPP.

In the LTE system, since the base station node (eNB: E-UTRAN NodeB) and the mobility management entity (MME) that manages mobility of the UE are connected in a full mesh form, the relationship between the eNB and the MME is N: M. Will have Therefore, if the eNB does not perform a load balancing function for the MME, there is a problem that all loads such as mobility management may be concentrated in a specific MME.

The present invention relates to a method and a mobile communication system capable of preventing load concentration when selecting a mobility management entity (MME) that manages mobility of a terminal in a base station node.

The load balancing mobile communication system of the present invention comprises: a plurality of MMEs (Mobility Management Entity) for forming and transmitting load balancing control information; And an eNB (E-UTRAN NodeB) for storing the load distribution control information and selecting the MME having the least load using the load distribution control information when a specific terminal is connected.

In addition, the load balancing method of the mobile communication system of the present invention comprises the steps of: a) forming load balancing control information; b) transmitting the load balancing control information; c) storing the load balancing control information; d) selecting the MME having the least load by using the load distribution control information when accessing a specific terminal.

According to the present invention, when there are a plurality of MMEs that can be selected by the eNB, not only can distribute the load for the management of the UE mobility of the MME, but also prevent the automatic selection of the MME even if a specific MME fails. It can improve the stability and reliability of the system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions will not be described in detail if they obscure the subject matter of the present invention.

1 is a block diagram showing the configuration of an LTE mobile communication system according to an embodiment of the present invention, Figure 2 is a flow chart showing the procedure of the load balancing method according to an embodiment of the present invention.

The LTE mobile communication system has mobility for the UE 10 on a user equipment (hereinafter referred to as UE) 10, a base station (hereinafter referred to as an eNB (E-UTRAN NodeB) 20) and an eNB 20. It includes a mobility management entity (MME) (30). The eNB 20 has a full-mesh shape that is connected to each of the MME 30. In addition, the MME 30 is connected to an IP network through an S-GW (Serving Gateway) 40 and a P-GW (PDN Gateway) 50. The control signal of the eNB 20 is transmitted to the S-GW 40 through the MME 30, and the user traffic is transmitted directly to the S-GW 40 without passing through the MME 30.

Looking at the load distribution method according to the present invention with reference to Figure 2, MME 30 forms the load distribution control information (S110). The load distribution control information includes an MME capacity indicating a processing capacity of the MME 30 and an MME load-level indicating a load sharing ratio for the processing capacity of the MME 30. The MME 30 transmits load balancing control information from the MME 30 to the eNB 20 using the IP multicast method (S120). The IP Multicast method will be described later. The eNB 20 receiving the load balancing control information stores the load balancing control information (S130), and when a specific UE 10 requests access to the eNB 20 (S140), the stored load balancing control information is used. The eNB 20 selects the MME 30 having the least load (S150). The specific UE 10 making the access request may access the upper layer through the selected MME 30.

First, referring to a communication method between the eNB 20 and the MME 30, the eNB 20 and the MME 30 communicate in a 1: 1 format at a specific moment such as mobility management or call processing, but in general, N You have to communicate with: M. To do this, use the IP Multicast method. In the IP multicast scheme, the lower layer may be different from IPv4 or IPv6 depending on the nature of the IP layer. Since the addressing address of the lower layer is changed and the operation itself is not changed, the present invention will be described based on the IPv4 address for convenience. The IP multicast scheme is performed from the MME 30 to the eNB 20, and the MME 30 transmits information such as its capacity and load level. Since the MME 30 needs to deliver information to multiple eNBs 20 at the same time, the IP multicast scheme is usefully used. IP Multicast addresses range from 224.x.x.x to 239.x.x.x, Class D addresses specified by the Internet Assigned Number Authority (IANA), of which one IP Multicast address is assigned. The assigned address is defined as IP_MULTICAST_LS.

3 is a block diagram showing the configuration of functional units of an eNB and an MME according to an embodiment of the present invention. Since the IP multicast method operates based on UDP / IP (User Datagram Protocol / Internet Protocol), as shown in FIG. 3, a corresponding protocol stack is added to the eNB 20 and the MME 30.

Referring to the operation of the MME load share block 31, the MME 30 includes a capacity and a current load state including mobility management for the UE 10 included in the load distribution control information. -level) is transmitted periodically (for example, LS_INTERVAL) to IP_MULTICAST_LS, which is an IP Multicast address.In addition to periodic transmission, certain event conditions, that is, its load status changes or is processed above a predetermined value (for example, 20% or more) Send over IP_MULTICAST_LS if more than 80% of the capacity is exceeded.

The processing capacity of the MME 30 is expressed in throughput per unit time, and the load state indicates the amount occupied in the processing capacity in%. Processing capacity and load state can be obtained by experiment.

MME pool id may be assigned to identify the MME 30 group in charge of load sharing with each other. Each MME 30 is assigned an MME id for identifying the MME 30. MME pool id and MME id are values previously assigned by the mobile communication system administrator, and load sharing is performed only within the same MME pool id.

The LS_INF message corresponding to the load balancing control information transmitted from the MME 30 to IP_MULTICAST_LS has a configuration as shown in FIG. 4. As can be seen from LS_INF message configuration, UDP / IP header including L1 / L2 is a format of message of general IP network, IP Multicast address assigned as IP_MULTICAST_LS is used as destination address of IP header, and page of UDP message is used. Payload includes MME pool id, MME id, MME capacity, MME load-level, and life-time. The MME pool id is a pool id to which the MME 30 that transmits the LS_INF message belongs, and the administrator may set a value in advance. The MME id is an MME id that transmits an LS_INF message, which an administrator may set in advance. The MME capacity is a total processing capacity such as mobility management of the MME 30 and is determined in advance for each system. The MME load-level is a load state that varies dynamically according to the operation of the MME 30 and has a range of 0 to 100%. Life-time is a valid period of a load-level transmitted by the MME 30 and may be set to a constant multiple (for example, three times) of LS_INTERVAL.

The operation of the load sharing block 21 of the eNB 20 is divided into IP multicast group management, LS_INF message reception processing procedure, and LS_TABLE usage method in relation to the load sharing of the eNB 20 to the MME 30. do.

1. IP Multicast group management

In order to receive the LS_INF message transmitted by the MME 30, the eNB 20 must perform a procedure of joining (IGMP-join) a predetermined IP_MULTICAST_LS group through the Internet Group Management Protocol (IGMP). If the eNB 20 no longer needs to receive the LS_INF message for IP_MULTICAST_LS, the eNB 20 may perform an IGMP-leave procedure. More specifically, when the IP_MULTICAST_LS group of the eNB 20 is changed, it is determined that it is no longer necessary to receive LS_INF for the existing IP_MULTICAST_LS group, and performs the IGMP-leave procedure, and performs the IGMP-join procedure for the changed IP_MULTICAST_LS group. To perform.

2. Process of Receiving LS_INF Message

The eNB 20 receives the LS_INF message transmitted by the MME 30 on a periodic or specific event condition through an IP multicast scheme. The eNB 20 analyzes the contents of the received LS_INF message and determines whether the MME pool id belongs to the eNB 20. If the MME pool id is not the pool id to which the eNB 20 belongs, discard the LS_INF message. If the MME pool id is the pool id to which the eNB 20 belongs, the MME id, MME capacity, MME included in the LS_INF message Fill the LS_TABLE value in Table 1 using load-level and life-time information.

MME id MME capacity MME load-level Life-time Dirty check

LS_TABLE in Table 1 is a table having MME id as a key value. When receiving an LS_INF message, a specific flag called Dirty Check is released and a timer is set based on a life-time value. If there is a timer already in progress in the MME id, the existing timer is released and a new timer is set. When the life-timed timer expires, Dirty Check is set to indicate that the LS_INF message did not arrive within the expected period from the MME.

3. How to use LS_TABLE

If the eNB 20 cannot select the MME 30 based on the information provided by the UE 10 with respect to the initial attachment request of the UE 10, the eNB 20 determines that the MME 30 is LS_INF. The MME 30 is selected by LS_TABLE shown in Table 1 based on the information transmitted through the message. The eNB 20 searches for LS_TABLE in Table 1, and the eNB 20 selects the MME 30 having the minimum MME load-level for the MME 30 in which the dirty check is released, thereby disconnecting the UE 20. Do it. That is, the MME 30 having a low level of load may handle the connection of the UE 10 so that the load for mobility management is uniformly distributed to the MME 30 in the MME pool. In the present embodiment, a method of selecting the most suitable MME 30 using the MME load-level information of LS_TALBE has been described, but the present invention is not limited thereto, and priority is given to a specific MME 30 according to a policy used by the mobile communication system. You can also choose how to do this.

While the above methods have been described through specific embodiments, the methods may also be implemented as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, which are also implemented in the form of carrier wave (eg, transmission over the Internet). It also includes. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

In addition, while the present invention has been described in connection with some embodiments, it is to be understood that various modifications and changes can be made without departing from the spirit and scope of the invention as will be understood by those skilled in the art. You will need to know It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

1 is a block diagram showing the configuration of an LTE mobile communication system according to an embodiment of the present invention.

2 is a flowchart illustrating a procedure of a load balancing method of a mobile communication system according to an exemplary embodiment of the present invention.

3 is a block diagram showing a configuration of functional units of an eNB and an MME according to an embodiment of the present invention.

4 is a block diagram showing a configuration of an LS_INF message according to an embodiment of the present invention.

Claims (14)

In a load balancing mobile communication system, A plurality of MMEs (Mobility Management Entity) for forming and transmitting load balancing control information; And And an eNB (E-UTRAN NodeB) for storing the load balancing control information and selecting the MME having the least load using the load balancing control information when a specific terminal is connected. The method of claim 1, The load distribution control information, MME capacity indicating the processing capacity of the MME, MME load-level indicating the load sharing ratio for the processing capacity of the MME, MME pool id for identifying the MME group responsible for load sharing, and identify each MME And a life-time for indicating an effective period of the load balancing control information. The method of claim 2, The load balancing control information is transmitted from the MME to the eNB using an IP multicast scheme. The method of claim 3, Transmission of load distribution control information using the IP multicast method is performed periodically or when the MME load-level is changed by more than a first predetermined value or when the MME capacity exceeds a second predetermined value. Communication system. The method of claim 4, wherein The IP multicast address used in the IP multicast method is a load balancing mobile communication system, characterized in that it assigns any one of an IANA (Internet Assigned Number Authority) Class D address range as an IP multicast address. 6. The method according to any one of claims 1 to 5, The eNB performs a procedure for subscribing to a specific group to receive the load balancing control information. The method of claim 6, The eNB stores the load balancing control information in a table form, The table is, When the load distribution control information is received, a timer is set based on the life-time, a flag is released, and the flag is set when the timer expires after the life-time has elapsed. Load balancing mobile communication system, characterized in that. In the load balancing method of a mobile communication system, a) forming load distribution control information; b) transmitting the load balancing control information; c) storing the load balancing control information; d) selecting the MME having the smallest load using the load distribution control information when a specific terminal is connected. The method of claim 8, The load distribution control information, An MME capacity indicating a processing capability of the MME; An MME load-level indicating a load sharing ratio for the processing capability of the MME; MME pool id for identifying MME group in charge of load sharing; An MME id for identifying each MME; And Life-time to indicate the valid period of the load balancing control information Load balancing method comprising a. 10. The method of claim 9, In step b), the load balancing control information is transmitted from the MME to the eNB (E-UTRAN NodeB) by using an IP multicast scheme. The method of claim 10, The load distribution control information transmission method using the IP multicast method is performed periodically or when the MME load-level is changed by more than a first predetermined value or when the MME capacity exceeds a second predetermined value. . The method of claim 11, The IP multicast address used in the IP multicast method is a load balancing method, characterized in that any one of an IANA (Internet Assigned Number Authority) Class D address range is allocated as an IP multicast address. The method of claim 12, The eNB performs a procedure for subscribing to a specific group to receive the load balancing control information. The method of claim 13, The eNB stores the load balancing control information in a table form, The table is, When the load distribution control information is received, the timer (Timer) is set based on the life-time, the flag (flag) is released, the load distribution method, characterized in that for setting the flag when the timer expires. .

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