KR20150061857A - Method and apparatus for call setup and mobile telecommunication system for the same - Google Patents

Abstract

Disclosed are a method and an apparatus for reducing the number of call setting steps, and a mobile communication system. The number of call setting steps is reduced by completing setting a bearer by reusing authentication information, which was successfully used in previous time, (without re-exchanging re-authentication and encryption/integrity algorithms) when bearer setting is failed (attachment rejection) after completing authentication between a terminal and a base station control apparatus. According to an embodiment of the present invention, when the bearer setting is failed, re-attempt possibility information is set; information for inter-authentication and security between the terminal and a network is stored and maintained based on the re-attempt possibility even when the bearer setting is failed. When bearer setting with one gateway is failed, another gateway capable of providing a service is selected based on information about a gateway capable of processing a call; and then a bearer setting request is issued to another gateway by reusing the information for inter-authentication and security based on the re-attempt possibility information.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a call setup method and apparatus, and a mobile communication system therefor.

The present invention relates to a method and apparatus for establishing a call in a mobile communication system. More particularly, the present invention relates to a method and apparatus for establishing a call in a mobile communication system, To complete the bearer setup without re-exchanging the bearer setup information (e.g., without re-exchanging the algorithm).

Recently, due to the rapid development of communication, computer network and semiconductor technology, not only various services using wireless communication networks have been provided, but the demand of users has been increasing day by day, and the global wireless Internet service market has been exploding Trend. Accordingly, a service provided by a mobile communication system using a wireless communication network is being developed not only as a voice service, but also as a multimedia communication service for transmitting various data.

Recently, with the increase of smart phones and the demand for data traffic, mobile operators are investing equipment and technology considering the system part and the influence to accommodate the increased data traffic in various ways.

Wireless data services of CDMA (Code Division Multiple Access) 2000, EV-DO (Evolution Data Only), WCDMA (Wideband CDMA), and WLAN (Wireless Local Area Network) have been commercialized. Recently, There has been a proposal for providing mobile communication services by installing an ultra-small base station in the indoor area so as to access a mobile communication core network through an indoor broadband network. In particular, in a next generation network system, a method of arranging a plurality of small-sized multi-cells (femtocells) as an alternative to satisfy a demand for a high data rate and stably providing various services is suggested. An ultra-small base station that manages such a femtocell is called an indoor base station or a femto base station. By reducing the size of the cell, the efficiency of a next generation network system using a high frequency band can be increased. In addition, the use of a plurality of small-sized cells is advantageous in terms of increasing the frequency reuse frequency. In addition, it is possible to improve the problem of deterioration of the channel condition due to the radio wave attenuation which occurred when one base station covers the entire cell area and the problem of inability to service the users in the shadow area, This has the advantage. Based on these advantages, a method of combining a macro cell (a cell area managed by an outdoor base station) and a femtocell (a cell area managed by an ultra-small base station such as an indoor base station or a femto base station) Is emerging.

Long Term Evolution (LTE) is a network for realizing requirements of high data rate, low-latency, and packet optimized radio access for an access network , And is designed to accommodate high-speed rich media while ensuring backward compatibility with existing 3GPP / non-3GPP access networks. LTE is an All-IP-based network that excludes existing circuit-switched based communications and enhances quality of service (OoS) management functions to provide real-time services (eg, voice communications, video communications) By providing differentiated QoS for real-time services (eg, web browsing, Store and Forward data transfer), we have increased the efficiency of network resources. In addition, by introducing smart antenna technology (ie, MIMO), the bandwidth for wireless communications has been extended.

In the Evolved Packet Core (EPC) network, which is an LTE core network, eNodeB <-> MME (Mobility Management Entity), MME <-> S-GW (Serving Gateway), and S-GW < Data Network Gateway) to perform call processing for voice and data processing. Security is crucial to secure call processing. To this end, the EPC network provides more secure security through mutual authentication, encryption and integrity algorithms.

After the authentication between the UE and the MME is completed and the encryption / integrity algorithm is negotiated, the MME requests bearer setup by selecting one of the plurality of S-GW / P-GWs. In this case, The S-GW may not be able to process the bearer setup request of the MME. In this case, the MME sends a bearer setup failure message (attach reject) to the UE. Then, the UE needs to re-issue an attach request to the MME and re-authenticate between the UE and the MME and re-exchange a new algorithm (encryption and integrity algorithm), so that the management server (MME, Home Subscriber Server (HSS) Etc.). Moreover, the user's dissatisfaction may be caused because the call processing service of the UE is restricted while re-authenticating and re-exchanging the new algorithm.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for performing a bearer setup failure by reusing previously successful authentication information (without re-authentication and re-encryption / integrity algorithm re-exchange) Thereby reducing a call setup step, and a mobile communication system therefor.

According to an aspect of the present invention, there is provided a method for establishing a bearer setup (re-authentication and encryption / integrity algorithm re-exchange) by reusing previously successful authentication information in a bearer setup failure And a mobile communication system therefor are disclosed. According to the present invention, retry enable information at the time of bearer setup failure is set, and information for mutual authentication and security between the terminal and the network is stored and maintained even when the bearer setup fails based on the retry enable information. In case of failure to establish a bearer with one gateway, after selecting another serviceable gateway based on the information of the gateway capable of handling the call, re-use information for mutual authentication and security based on the retryable information, request.

According to the present invention, the message processing procedure (re-authentication and not re-exchanging the encryption / integrity algorithm) can be reduced as the bearer setting failure is retried by a value set on one flow without immediately performing failure processing There is an advantage.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a configuration of an exemplary mobile communication network in which the present invention can be implemented; Fig.
2 is a diagram showing an embodiment of an EPC network to which the present invention can be applied;
3 is a diagram illustrating a call processing procedure for packet and voice service support in an EPC network to which the present invention can be applied.
4 illustrates an authentication procedure for call processing to which the present invention can be applied;
5 is a diagram showing the configuration of a call setting device according to an embodiment of the present invention.
6 is a flowchart illustrating a call setup method according to an embodiment of the present invention.

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.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a configuration of an exemplary mobile communication network in which the present invention can be implemented. Fig.

In one embodiment, the mobile communication network includes a wireless network such as a Global System for Mobile communication (GSM), a 2G wireless communication network such as CDMA, an LTE network, a wireless Internet such as WiFi, a Wireless Broadband Internet (WiBro), and a World Interoperability for Microwave Access (E.g., 3G mobile communication network such as WCDMA or CDMA2000, High Speed Downlink Packet Access (HSDPA) or 3.5G mobile communication network such as HSUPA (High Speed Uplink Packet Access), or the like A 4G mobile communication network currently in service, and any other mobile communication network including a macro base station (macro eNodeB), a micro base station (Pico eNodeB, Home eNodeB), and a terminal UE. It is not. Hereinafter, an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) as a radio access network of LTE will be mainly described.

As shown in FIG. 1, the mobile communication network may include one or more network cells, and may include a HetNet environment in which different kinds of network cells may be mixed in a mobile communication network. The mobile communication network includes miniature base stations (Pico eNodeB, Home-eNodeB, relay, etc.) 11 to 15, 21 to 23, and the like, which manage small-sized network cells (e.g., 'small cells' such as picocells, femtocells, (MAC) eNodeBs 10, 20, and 30, a UE 40, and SON (Self Organizing & Optimizing) devices 40 and 40 for managing a wide range of cells (e.g., 'macro cells' (MSS) 60, an S-GW (Serving Gateway) 80, a P-GW (Packet Data Network) gateway 90 and an HSS (Home Subscriber Server) (100). The number of each component shown in FIG. 1 is illustrative, and the number of each component of the mobile communication network in which the present invention can be implemented is not limited to the number shown in the drawings.

For example, the macro base stations 10, 20 and 30 can be used in an LTE network, a WiFi network, a WiBro network, a WiMax network, a WCDMA network, a CDMA network, a UMTS network, But is not limited to, the characteristics of the macro cell base station that manages the base station.

The micro base stations 11 to 15 and 21 to 23 and 31 to 33 may be used in an LTE network, a WiFi network, a WiBro network, a WiMax network, a WCDMA network, a CDMA network, a UMTS network, but is not limited to, the features of a pico base station, an indoor base station or a femto base station, or a relay that manages a cell having a radius of about m to several tens of meters.

The micro base stations 11 to 15, 21 to 23, and 31 to 33 and the macro base stations 10, 20, and 30 can independently have connectivity of the core network.

The UE 40 is used in a portable Internet network such as a GSM network, a 2G wireless communication network such as a CDMA network, a wireless Internet network such as an LTE network and a WiFi network, a WiBro network and a WiMax network or a mobile communication network supporting packet transmission But is not limited to, the characteristics of the mobile terminal.

The management server (O & M server) 70, which is a network management apparatus of the micro-base station, is responsible for configuration information and management of the micro base stations 11 to 15, 21 to 23, and 31 to 33 and the macro base stations 10, . The management server 70 can perform all the functions of the SON server 50, the MME 60, and the HSS 100. [ SON server 50 may include any server that performs macro / micro base station installation and optimization and functions to provide basic parameters or data necessary for each base station. The MME 60 may include any entity used to manage the mobility of the terminal 40 and the like. In addition, the MME 60 performs a function of a base station controller (BSC), and allocates resource allocation, call control, handover control, voice and packet processing control to the base stations (pico eNodeB, home eNodeB, macro eNodeB, And so on. The HSS 100 is a kind of database for service / authentication of the subscriber.

In one embodiment, one management server 70 can perform all the functions of the SON server 50, the MME 60, and the HSS 100, and the SON server 50, the MME 60, The base station 100 can manage one or more macro base stations 10, 20 and 30 and one or more micro base stations 11 to 15, 21 to 23 and 31 to 33.

Although it is assumed that a macro cell, a pico cell, and a femtocell are mixed in the mobile communication network, the network cell may be composed of a macro cell, a pico cell, and a macro cell.

Access to the macro base stations 10, 20 and 30 is generally permitted for all terminals, but access to the micro base stations 11 to 15 and 21 to 23 and 31 to 33 is restricted to a specific terminal (subscriber) There is an operational function that can be done. This is called a connection mode or an operation mode, and the connection mode of the micro base stations 11 to 15, 21 to 23, and 31 to 33 is classified according to which terminal is provided with a service. That is, a closed connection mode, an open connection mode, and a hybrid connection mode. A closed access mode (closed access mode or CSG closed mode) allows access only to a specific subscriber, and an open access mode (CSG open mode) is a mode in which any subscriber can connect without a connection permission condition, Hybrid) can be regarded as a compromise type.

Specifically, the micro-base stations 11 to 15, 21 to 23, and 31 to 33 can broadcast SIB 1 (System Information Block type 1), which is system information, to the femtocell area managed by itself. And a CSG indicator (Closed Subscriber Group indicator) indicating whether access to the femtocell is restricted. SIB 1 is a message that a base station (HeNB, macro eNB) broadcasts information about its own cell to all the terminals 40. The SIB 1 includes a CGI (Cell Global Identity) (a unique cell identifier in the network), a CSG indication , A CSG ID (ID for CSG), and the like.

When the mobile communication network is assumed to be an LTE network, the LTE network is interworked with an inter-RAT network (WiFi network, WiBro network, WiMax network, WCDMA network, CDMA network, UMTS network, GSM network, etc.). (LTE network, WiFi network, WiMax network, WCDMA network, CDMA network, UMTS network, GSM network, etc.) when one of the inter-RAT networks (e.g., WiBro network) is the mobile communication network. (WiFi network, WiMax network, WCDMA network, CDMA network, UMTS network, GSM network, etc.) are shown apart from each other in the drawing, it is assumed that it is overlaid.

When the micro base stations 11 to 15, 21 to 23 and 31 to 33 and / or the macro base stations 10, 20 and 30 are collectively referred to as a 'base station device', the base station device (eNB 25 in FIG. The E-UTRAN comprises an IP-based flat structure and processes data traffic between the terminal 40 and the core network. The signal control between them is performed by the MME 60. The MME 60 takes charge of signal control between the base station device 25 and the S-GW 80 and decides where to route the incoming data from the terminal 40. The S-GW 80 performs an anchor function between the base station device 25 and the base station device 25 to move a terminal between the 3GPP network and the E-UTRAN, . The MME 60 / S-GW 80, which is a core network equipment, manages a plurality of base station devices 25, and each base station device 25 is composed of a plurality of cells. The C-plane / U-plane is controlled through the S1 interface between the base station device 25 and the MME 60 / S-GW 80, and the X2 interface is used for handover between the base station device 25 and the SON function. do.

The setup of the network interface is accomplished by setting up the S1 interface connecting with the MME 60 at the center of the system and the X2 interface, which is a network line for direct communication with the base station device 25 of other cells present on the current system. The S1 interface exchanges operation and management (OAM) information to support the movement of the UE 40 by exchanging signals with the MME 60. [ In addition, the X2 interface exchanges signals for the fast handover between the base station apparatuses 25, load indicator information, and information for self-optimization.

Referring to FIG. 2, a configuration of an EPC (Evolved Packet Core) network to which the present invention can be applied will be described. A call processing process for supporting packet and voice services in an EPC network will be described with reference to FIG. .

2 is a diagram showing an embodiment of an EPC network to which the present invention can be applied.

The E-UTRAN is an LTE radio access network composed of a base station apparatus (eNB) 25, is IP-based, and is located between the UE 40 and a wireless communication core network to transmit data and control information. In addition, a paging request for CS fallback, a function for delivering an SMS message to the UE 40, and a direct connection to a target cell capable of a CS service are supported.

2, "LTE-Uu" represents a radio interface between the E-UTRAN and the UE 40, "S1- MME" is an interface between the E-UTRAN (base station apparatus 25) and the MME 60, "S1-U" is an interface between the E-UTRAN (base station apparatus 25) and the S-GW 80. "S5 / S8" is an interface between the S- to be. And "SGi" is an interface between the P-GW 90 and the IP network.

The UE 40 and the eNB 25 of the E-UTRAN communicate via the Radio Resource Control (RRC) protocol and a broadcasting message to the cell area controlled by the eNodeB 25 by itself RRC message. The RRC message may include control messages from the Non-Access Stratum (NAS) protocol, which control messages are transmitted transparently to the UE 10 or the core network without being read in the E-UTRAN.

The eNB 25 is an end point for the radio signal of the E-UTRAN and the control signal is interlocked with the MME 60 via the S1-MME interface and the data traffic is interworked with the S-GW 80 via the S1- do. The S-GW 80 performs a buffering function for anchor and downlink traffic for mobility in the E-UTRAN. The P-GW 90 is an external IP network connection point, and performs IP allocation and billing for a mobile subscriber and traffic control functions for user data.

The data traffic downloaded from the EPC network is transmitted through the mapping between the SGi interface, the S5 / S8 interface, the S1-U interface, and the LTE-uu interface section.

The IP network provides an IMS (IP Multimedia Subsystem) service for the UE 40 in the EPC network, and includes Policy & Charging Rule Function (PCRF), IMS nodes (for example, Proxy Call Session Control Function (P-CSCF) (Interrogating Call Session Control Function (CSCF), Serving Call Session Control Function (S-CSCF), Application Function (AF)), and the like.

UE 40 sends and receives a call control message for multimedia services using IMS nodes and the Gm interface through an EPC bearer (provided by E-UTRAN / S-GW / P-GW).

The E-UTRAN 25 provides a radio communication function to the UE 40 and performs a function of managing radio resources for the radio communication function.

The MME 60 may receive authentication information for authenticating the UE 40 from the HSS 100 and perform authentication of the UE 40. [ In addition, the MME 60 manages the mobility of the UE 40 and the base station apparatus 25 in the upper layer of the base station apparatus 25, and can perform a call control function such as bearer setup / release. In addition, the MME 60 can be directly connected to the IP network through the S-GW 80 and the P-GW 90. The call processing control signal of the base station apparatus 25 is transmitted to the S-GW 80 via the MME 60 and is transmitted to the P-GW 90 in response to the call processing control signal, Lt; / RTI &gt;

The S-GW 80 acts as a gateway between the 3GPP network and the E-UTRAN 25 and performs handover between the base station apparatus and the base station apparatus (inter-eNodeB) and between the 3GPP network and the 3GPP network (inter-3GPP) 40 to provide mobility. The S-GW 80 can transmit a job required for call processing to the P-GW 600 according to the control signal of the base station device 25. [

The P-GW 90 may allocate an IP address to the UE 40 and apply different QoS policies to the UE 40. [ In addition, the P-GW 90 acts as a gateway to a PDN (Packet Data Network), allowing the UE 40 to access a data network such as the Internet or the Internet to receive services.

The S-GW 80 and the P-GW 90 are separated and communicate with each other via the S5 / S8 interface. However, the S-GW 80 and the P-GW 90 may be implemented as a single gateway .

The HSS 100 may manage authentication information for authenticating the UE 40, location information of the UE 40, and the profile of the UE 40. [ The profile of the UE 40 may include QoS rating information (e.g., priority, maximum available bandwidth, etc.) for each service item to which each UE 40 subscribes. In one embodiment, the authentication information for authenticating the UE 40 and the profile of the UE 40 may be transferred from the HSS 100 to the MME 60 when the UE 40 connects to the network.

The PCRF (not shown) manages policies and rules for charging and allows the P-GW 90 and the S-GW 80 to provide appropriate QoS for the UE 40 and use Allows you to perform the billing function for the bearer.

The IMS node (not shown) is made up of nodes such as P-CSCF, I-CSCF, S-CSCF, and AF in detail and the UE 40 provides multimedia services such as VoIP give.

3 is a diagram illustrating call processing procedures for supporting packet and voice services in an EPC network to which the present invention can be applied.

When the UE 40 requests the MME 60 to perform call processing through the E-UTRAN, the MME 60 receives the subscriber information for the UE 40 from the HSS 100. The bearer for packet transmission is established by the S-PW 80 / P-GW 90 by constructing various information necessary for the call processing, and the UE 40 responds.

Specifically, in order to receive the packet service and the voice service, the UE 40 first transmits a call setup request message to the radio section (s301).

The eNodeB 25 of the E-UTRAN forwards the call processing request message received from the UE 40 to the MME 60 (s302), and the MME 60 transmits the call processing request message The HSS 100 requests information for preparation of call setup with the UE 40 and receives information for preparation of call setup from the HSS 100 at step S303.

The MME 60 selects one of the plurality of S-GWs 80 / P-GWs 90 using the information received from the HSS 100 and requests a bearer setup.

When the bearer setup is completed (S304), the packet service and voice service for the UE 40 are possible. At this time, upon completion of the bearer setup with the S-GW 80 / P-GW 90, the MME 60 transmits a completion message (attach complete) for the attach request of the UE 40 to the user And informs that the resource allocation for the network has been granted and assigned in the network. However, when the bearer setup with the S-GW 80 / P-GW 90 fails, the MME 60 sends an attach reject message for the attach request of the UE 40, The UE and the MME must re-authenticate and re-exchange the new algorithms (encryption and integrity algorithms). The re-authentication in case of bearer establishment failure and the encryption / integrity algorithm re-exchange process will be described in detail later.

4 is a diagram showing an authentication procedure for call processing to which the present invention can be applied. In the call processing procedure of FIG. 3, mutual authentication between the UE 40 and the network (MME 60) .

During authentication between the UE 40 and the MME 60, the HSS 100 exchanges authentication key values received from the HSS 100 and performs mutual authentication based on the authentication key values. It also tells the security mode command which encryption and integrity algorithms to use for each other.

Specifically, when the UE 40 requests the initial call processing (S401), the MME 60 requests authentication information from the HSS 100 and receives the authentication key value (S402). Based on the authentication key value, the UE 40 authenticates the network (MME 60), and the MME 60 authenticates the authentication key value transmitted by the UE 40 and the authentication key value received from the HSS 100 And performs mutual authentication by performing authentication with respect to the UE 40 (S403).

When the mutual authentication is completed (S403), the MME 60 determines an algorithm to be used for integrity and encryption and informs the UE 40 (S404). Based on this encryption and integrity algorithm, the UE 40 encrypts and delivers the message to the MME 60 at the time of call processing, and the MME 60 checks the integrity of the message encrypted and transmitted from the UE 40 . The UE 40 can check the integrity of the message transmitted from the MME 60 to the UE 60.

For reference, a process of processing a message that is encrypted and transmitted based on an encryption and integrity algorithm will be described. When the UE 40 transmits an encrypted message based on the encryption and integrity algorithm to the MME 60 40), the MME 60 generates a MAC based on its own authentication key value and the encryption and integrity algorithm to compare whether the MAC values match. As a result of the comparison, if the MAC values match, it is determined that the integrity of the message transmitted from the UE 40 is guaranteed (i.e., integrity is successful), and the call processing is performed. If the MAC values do not match, it is determined that the integrity of the message transmitted from the UE 40 is not ensured (i.e., integrity failure), and the corresponding message is rejected.

After the authentication between the UE 40 and the MME 60 is completed and the encryption / integrity algorithm is negotiated, the MME 60 determines whether the S- GW 80 or P-GW 90 to request a bearer setup. At this time, if the S-GW 80 fails to process the bearer setup request of the MME 60 in an unexpected situation Situations can arise. In this case, the MME 60 sends a bearer setup failure message (attach reject) to the UE 40. The UE 40 must then re-issue an attach request to the MME 60 and re-authenticate and re-exchange the new algorithm (encryption and integrity algorithm) between the UE 40 and the MME 60 (The process of FIG. 4 is performed again).

To accomplish this, in the present invention, the bearer setup is completed by reusing previously successful authentication information (without re-authentication and re-exchanging the encryption / integrity algorithm) in case of an attach reject. Previously successful authentication information includes authentication information for mutual authentication between the UE and the network (that is, information enabling authentication between the UE and the authentication center, information enabling authentication between the UE and the MME), the UE 40, And encryption / integrity algorithm information exchanged between the MME 60 and the MME 60 for encryption and integrity.

5, a configuration of a call setup apparatus according to the present invention may include a storage unit 501, a communication unit 502, a control unit 503, and a call processing management unit 504. The call setup apparatus of the present invention selects one of several S-GWs 80 / P-GWs 90 for a call processing request message of the UE 40 to request a bearer setup Can be used. It may be included in the MME 60, but it may be provided separately from the MME 60.

The call processing management unit 504 can select another serviceable gateway based on the information on the gateway that can process the call when the bearer setting with one gateway fails. The function of each component is as follows.

The storage unit 501 may store information on a gateway capable of processing a call (S-GW 80 or P-GW 90). In one embodiment, the information about the callable gateway may include information about the incapability or possible status of the gateway. The service disabled or possible state of the gateway can be set in the control unit 503. [ In addition, the information on the gateway capable of call processing may include information on the IP address of the gateway. However, the information on the gateway capable of call processing is not limited to the above-described embodiment, but may be any information as long as it can indicate the state of the gateway and can identify the gateway. In addition, the storage unit 501 may store mapping information for a gateway to perform call processing according to a subscriber identification number (for example, International Mobile Station Identity (IMSI)). As shown in Table 1 below, the call processing of the subscriber identification numbers 00001 to 10000 is performed by the first gateway, the call processing of the subscriber identification numbers 10001 to 20000 is performed by the second gateway, May store mapping information that the third gateway can perform. However, the gateway for performing the call processing according to the subscriber identification number is not limited to the above embodiment.

The first gateway The second gateway The third gateway . . . Subscribers
Identification number XXXXXX000000001 - XXXXXX000010000 XXXXXX0000010001 to XXXXXX0000020000 XXXXXX0000020001 to XXXXXX0000030000 . . .

When receiving the call processing request message through the communication unit 502, the call processing management unit 504 extracts the subscriber identification number included in the call processing request message, and maps the extracted subscriber identification number to the gateway Information can be fetched from the storage unit 501. [ The call processing management unit 502 may transmit the received call processing request message to the gateway corresponding to the mapping information using the retrieved mapping information. In addition, when the gateway receiving the call processing request message can not perform the call processing due to a sudden load, the call processing management unit 504 receives the call processing failure message and stores information about the gateway capable of performing call processing in the storage unit 501 And transmits the call processing request message to the gateway corresponding to the fetched information again. In one embodiment, if at least two pieces of information about a gateway capable of call processing are stored in the storage unit 312, the call processing management unit 504 selects a gateway having the highest priority and transmits a call processing request message to the selected gateway Lt; / RTI &gt; The priority of the gateway can be set in inverse proportion to the call processing load. For example, the priority of the gateway with the lowest call processing load can be set to the highest priority, and the priority of the gateway with the highest call processing load can be set to the lowest priority.

When receiving the call processing failure message from the gateway, the control unit 503 sets the information on the corresponding gateway stored in the storage unit 501 to the service disabled state. After the predetermined period of time has elapsed after setting the service disabled state, To the serviceable state. In one embodiment, the user can select and set a predetermined time of 5 seconds, 10 seconds, 30 seconds, 60 seconds, or the like. In addition, when receiving a call process success message from the gateway, the control unit 503 can request bearer setup to the corresponding gateway.

The communication unit 318 can receive a call processing request message from the base station, send a call processing request message to the gateway set in the call processing management unit 314, receive a call processing failure message and a call processing success message from the gateway .

In particular, the storage unit 501 stores information for mutual authentication and security between the terminal and the network (that is, information about the S-GW 80 or P-GW 90) An authentication key value received from the HSS 100, an algorithm (encryption and integrity algorithm) information used for integrity and encryption), and retry enable information at the time of gateway and bearer setup failure. The retry enable information may include retry enable time or retry enable time information. In general, information for mutual authentication and security between the UE and the network is deleted when the bearer setup fails, but is maintained for a predetermined time or retry times according to the retryable information in the storage unit 501 of the present invention.

The retry-able time information is the time allowed to re-request previously configured authentication information (without re-authentication and re-exchanging the encryption / integrity algorithm) to re-request the bearer setup to another gateway in case of bearer setup with one gateway For example, 10, 20, 30 seconds, or the like).

The retry enable time information can be determined by referring to the current failure times information when the bearer setting fails and the allowable retry times. If the number of failures is known, it is possible to know the number of retries based on the allowable number of retries, and the number of retries is within the allowable number of retries. For example, if the number of allowable retries is set to A (A is a natural number), if the current number of failures is B (B is a natural number), the number of retries C (C is a natural number) is "A-B + 1" C is less than or equal to A. That is, when the allowable number of retries is set to "5", if the current number of failures is "2", the number of retries is "4". The number of times that retries can be performed means the number of retries (that is, re-requesting bearer setup) on one flow without immediately performing a failure process when the bearer setup fails.

Upon receiving the call processing request message from the UE 40 through the communication unit 502, the control unit 503 requests authentication information from the HSS 100 to transmit and control the received authentication key value to the UE 40, (501). Based on the authentication key value, the control unit 503 performs authentication for the UE 40, and the UE 40 can also perform authentication for the MME 60. Thereafter, when the mutual authentication between the UE 40 and the MME 60 is completed, the controller 503 determines an algorithm to be used for integrity and encryption and forwards it to the UE 40 and controls the algorithm. Based on this encryption and integrity algorithm, the UE 40 encrypts and delivers the message to the MME 60 upon call processing, and the MME 60 checks the integrity of the message encrypted and transmitted from the UE 40 Selects one of several S-GW 80 / P-GW 90 for the call processing request message of the UE 40, which is determined to be integrity-guaranteed, to request a bearer setup. When the bearer setup fails, the control unit 503 reuses the authentication information for mutual authentication between the terminal and the network stored in the storage unit 501 and the algorithm / encryption / integrity information based on the retry enable information, ) To request the bearer setup from the other gateway.

If the retry enablement information is set to time, the control unit 503 reuses the information stored in the storage unit 501 within a designated time range, and requests the other gateway selected by the call processing management unit 504 to sequentially set bearer.

When the retry enable information is set to the number of times, the control unit 503 stores (updates) / controls the current failure count information in the storage unit 501, and stores the current failure count information stored in the storage unit 501 and the retry enable information It is determined whether or not retries are possible based on the number of times of retry on the basis of the number of retries, and the information stored in the storage unit 501 is reused for the number of retries that can be retried and the bearers are sequentially set to the other gateways selected by the call processing management unit 504 Lt; / RTI &gt;

6 is a flowchart illustrating a call setup method according to an embodiment of the present invention.

In order to receive the packet service and the voice service, the UE 40 first transmits a call setup request message to the radio section (s601).

The eNB 25 of the E-UTRAN forwards the call processing request message received from the UE 40 to the MME 60 (s602), and the MME 60 transmits the call processing request message to the MME 60 The HSS 100 requests information for preparation of call setup with the UE 40 and receives information for preparation of call setup from the HSS 100 at step S603.

The MME 60 selects one of the plurality of S-GWs 80 / P-GWs 90 using the information received from the HSS 100 and requests a bearer setup.

That is, the call processing control signal of the eNB 25 is transmitted to the S-GW 80 via the MME 60, and a work necessary for call processing is transmitted to the P-GW 90 according to the control signal. Authentication between the UE 40, the eNB 25, and the MME 60 is required to perform the procedure of FIG. The UE 40 needs to confirm the network and the MME 60 that the UE 40 is currently desiring to receive the service and the UE 40 needs to be verified in the eNB 25 and the MME 60 . Accordingly, mutual authentication is performed between the UE 40 and the MME 60. When the mutual authentication is completed, the MME 60 determines an algorithm to be used for integrity and encryption and notifies the UE 40 of the algorithm. Based on this encryption and integrity algorithm, the UE 40 encrypts and delivers the message to the MME 60 at the time of call processing, and the MME 60 checks the integrity of the message encrypted and transmitted from the UE 40 . The MME 60 requests bearer setup by selecting one of the various S-GW 80 / P-GW 90 for the call processing request message of the UE 40 that is determined to be integrity-guaranteed. The S-GW 80 may not be able to process the bearer setup request of the MME 60 in the unexpected state. In this case, the call processing management unit 504 of the MME 60 selects another serviceable gateway based on the information on the gateway capable of call processing when bearer setting with one gateway fails (s604), and the control unit 503 Re-use authentication information and encryption / integrity algorithm information stored in the storage unit 501 based on the retry enable information, and request bearer setup to another gateway (s605).

When the bearer setup is completed, the MME 60 transmits a bearer setup complete message to the UE 40 to inform that the resource allocation for the user has been approved and allocated in the network (s606).

Although the method has been described through particular embodiments, the method may also be implemented as computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

Although the present invention has been described in connection with some embodiments thereof, it should be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention as understood by those skilled in the art. something to do. It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

25: eNB (evolved-NodeB) 40: UE (User Equipment)
60: MME (Mobility Management Entity) 80: S-GW (Serving Gateway)
90: P-GW (PDN Gateway) 100: Home Subscriber Server (HSS)

Claims (9)

As a call setup method,
a) setting retry enable information when a bearer setup failure occurs, and storing and maintaining information for mutual authentication and security between the terminal and the network even if bearer setup fails based on the retry enablement information;
b) selecting a serviceable gateway based on information on a gateway capable of handling a call when bearer establishment fails with one gateway; And
c) re-using information for mutual authentication and security based on the retry enablement information, and requesting bearer establishment to the other gateway. The method according to claim 1,
Wherein the information for mutual authentication and security includes authentication information for mutual authentication between the terminal and the network, and algorithm information for encryption and integrity. The method according to claim 1,
Wherein the retry enable information is retry enable time or retry enable time information. The method according to claim 1,
Wherein the information on the call processable gateway includes information on an IP address of the call processable gateway. As a call setup device,
Retry enable information at the time of bearer establishment failure and information for mutual authentication and security between the terminal and the network even if the bearer setup fails based on the retry enable information;
A call processing manager for selecting another serviceable gateway based on information on a gateway capable of handling a call when bearer setting fails with one gateway; And
And a control unit for re-using information for mutual authentication and security based on the retry enablement information stored in the storage unit and requesting bearer establishment from another gateway selected by the call processing management unit. 6. The method of claim 5,
Wherein the information for mutual authentication and security includes authentication information for mutual authentication between the terminal and the network, and algorithm information for encryption and integrity. 6. The method of claim 5,
Wherein the retry enable information is retry enable time or retry enable time information. A mobile communication system,
Information for mutual authentication and security between the terminal and the network is stored and maintained even if the bearer setup fails based on the retry enablement information, and a bearer setup failure with one gateway A gateway control unit that selects another serviceable gateway based on information on a gateway capable of performing call processing and reuses information for mutual authentication and security based on the retry enablement information, Wherein the mobile communication system comprises: 9. The method of claim 8,
The information for mutual authentication and security includes authentication information for mutual authentication between the terminal and the network, algorithm information for encryption and integrity,
Wherein the retry enable information is retry enable time or retry enable time information.

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