KR20060066600A - Internet protocol based mobile communication system and session establishment method thereof - Google Patents

Abstract

The present invention relates to a mobile communication system based on the Internet Protocol and a session establishment method thereof.

In a mobile communication system based on the Internet protocol, a session establishment procedure using SIP is performed for real-time mobile multimedia communication such as voice and video call using Session Initiation Protocol (SIP). At this time, not only the multimedia codec but also session information and QoS (Quality of Service) information are negotiated with each other between the calling terminal and the called terminal and the related network elements in the pass-through section. The access manager controls the mobile access router, which is a gateway serving as a gateway of the access network according to the negotiated session information and OoS. This eliminates the need for a separate QoS negotiation procedure to open a QoS guaranteed session between the terminal and the mobile access router, between the mobile access router and the mobile access router, and between the mobile access router and the called terminal. As a result, it is possible to simplify the session setup time and procedure for real-time multimedia communication of the mobile communication network.

IP, session setup, QoS, access router

Description

Internet communication based mobile communication system and its session setting method

1 is a schematic structural diagram of a mobile communication network to which a session establishment method according to an embodiment of the present invention is applied.

2 is a flowchart illustrating a step-by-step session establishment process for multimedia communication in which a general end-to-end QoS is guaranteed.

3 is a detailed structural diagram of an internet protocol based mobile communication system for performing session establishment according to an embodiment of the present invention.

4 is a flowchart illustrating a session establishment process for guaranteeing end-to-end service quality according to an embodiment of the present invention based on the structure shown in FIG. 3.

The present invention relates to a mobile communication system based on the Internet Protocol (hereinafter, also referred to as IP), and more specifically, to an IP-based mobile communication system and session establishment for real-time voice and video calls in the system. It is about how to set up a session using the Session Initiation Protocol (SIP).

Currently, the IETF, which is in charge of Internet standards, proposes a Session Initiation Protocol (SIP) / Session Description Protocol (SDP) protocol that performs session control functions over an IP-based network, which is a multimedia service such as Voice Over IP (VoIP) Used as a signaling protocol that can provide. SIP is a text-based protocol such as HTTP (Hyper Text Transfer Protocol). It is currently used for establishing sessions in various fields, including Internet telephony, and can be serviced anywhere and anytime by using an address system using a Uniform Resource Identifier (URI). Personal Mobility is provided.

In addition, research on 3GPP or after 3G mobile communication service that considers not only voice service but also data service and can receive service anywhere in the world is being actively conducted in 3GPP. In particular, the GPRS (General Packet Radio Service) system proposed in 3GPP Release 5 considers a session control protocol such as session management (SM) for packet-based multimedia services and implements IP-based real-time multimedia session control. For this purpose, we consider the SIP / SDP protocol proposed by the IETF.

In accordance with this trend, active researches are being conducted on multimedia session establishment procedures and contents using the session establishment protocol. The procedure currently underway by the standardization organization suggests how to negotiate network resources based only on the codec type to establish an end-to-end quality of service (QoS) multimedia session. From the terminal to the router or gateway of the network and the terminal of the terminal to ensure the session quality for the call setup of the desired type. In addition, in the network resources to be negotiated, not only the codec types but also methods for QoS negotiation, that is, resource reservation protocol (RSVP) or DiffServ. Negotiations are also being made on how to negotiate differentiated services, and how to include other network resources.

Meanwhile, after the negotiation procedure for session establishment is completed, the negotiated end-to-end QoS is negotiated between the starting terminal, the gateway or access router along the traffic path of the network, and the terminal of the end using the negotiated information. Will begin the process. The main methods used for this purpose are the integrated service method (IntServ) and the differentiated service method (DiffServ). Therefore, to meet end-to-end QoS, one method or multiple methods suitable for the network environment are used.

However, conventionally, the end-to-end QoS negotiation procedure for opening a QoS guaranteed session between a mobile access router and a called terminal after a negotiation procedure for establishing a session is performed. Thus, the number of protocol messages exchanged between the terminal and the base station and the processing of the protocol messages are handled. There is a problem that the time is increased, the overall session establishment time is increased, and the procedure is also complicated.

An object of the present invention is to provide a session establishment method that can satisfy QoS in real time multimedia communication in an IP-based mobile communication system.

Another object of the present invention is to provide a mobile communication system and a session establishment method thereof that can be performed more efficiently and simply for real-time multimedia communication.

In accordance with an aspect of the present invention, a method for establishing a session in an IP-based mobile communication system is an access network connected through a network between a terminal and a core network, and includes a base station wirelessly connected to the terminal and the base station. A method for establishing a session of an IP-based mobile communication system, comprising: a gateway connected to and performing routing; and an access manager for controlling a network connection through the gateway. Establishing a wireless control channel for transmission; (b) the base station receives a session establishment request from the terminal through the established radio control channel, and exchanges a message between the terminal and a serving-call session control function (S-CSCF) of the core network through the gateway; Simultaneously performing a session control procedure, resource allocation, and QoS negotiation in a radio section; And c) allowing the access manager to control the operation of the gateway to transmit traffic to the terminal based on the session information, QoS information, and resource allocation information obtained by performing the session control procedure in the step. .

In an IP-based mobile communication system according to another aspect of the present invention, in an IP-based mobile communication system connected between a mobile communication terminal and a core network, the mobile station is connected to a base station connected to the mobile communication terminal to perform routing. Gateway; And receiving a session establishment request from the terminal and exchanging messages between the terminal and a Serving-Call Session Control Function (S-CSCF) of the core network through the gateway, thereby performing a session control procedure, resource allocation and QoS in a radio section. It includes an access manager that allows negotiation to be performed simultaneously.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention.

1 is a block diagram schematically illustrating a structure of a general IP-based mobile communication network.

Referring to FIG. 1, the mobile communication network 10 includes an access network 200 wirelessly connected to the terminal 100 and a core network 300 connected to the access network and configured as an IP network.

2 illustrates a general session procedure in such a mobile communication network. 2 is a diagram illustrating a session process when a mobile multimedia call is made between terminals in the mobile communication network 100. In detail, the following describes a mobile multimedia session establishment procedure and QoS negotiation procedure in which QoS is guaranteed in a mobile multimedia call between a calling terminal and a called terminal.

As shown in FIG. 2, first, in a first step, a procedure of controlling a session of a wireless section according to a general procedure of a mobile communication system using SDP is performed. For example, only the resources of the codec provided in the terminal and the intermediate node can be negotiated, or more specifically, the network resources and the QoS negotiation scheme as well as the type of codec can be negotiated.

As a next second step, after the negotiation for the session establishment of the first step is completed, a QoS negotiation procedure for guaranteeing QoS is performed. The first step is a negotiation process between control function elements of the network element, and the second step is a negotiation process between the related traffic delivery functions for traffic delivery. Thus, sessions with guaranteed QoS are connected to end to end.

Next, as a third step, the multimedia call step is performed. That is, after the sessions of which QoS is guaranteed for the end-to-end through the process of the first step and the second step, the multimedia call of voice or voice / video is made through this session.

As described above, in the IP-based mobile communication system, in order to establish a real-time multimedia session that guarantees end-to-end QoS, a session establishment process (first stage), QoS negotiation process (second stage), and end-to-end traffic transmission process (third stage) Step 3) should be performed. This IP-based Multimedia Subsystem (IMS) has been newly introduced for the management of multimedia sessions in IP-based mobile communication networks, and it performs management functions such as session establishment / release using SIP. This is because they are pursuing integration in a range that does not involve each other in the combination of Internet and Internet technologies.

However, in the IP-based mobile communication system pursuing the next generation, a close combination of the Internet and mobile communication must be made for effective system implementation. Therefore, an embodiment of the present invention is to propose a function and control method of an IP-based mobile communication access network element to improve the session establishment procedure and implement it. In particular, this paper proposes a function and control method of IP-based mobile communication access network element that simplifies the session establishment procedure by implementing a close technical combination of the Internet and mobile communication.

3 illustrates the structure of an IP-based mobile communication system for establishing a session in an embodiment of the present invention.

As shown in FIG. 3, in the mobile communication system according to an exemplary embodiment of the present invention, the access networks 210 and 220 are wirelessly connected to the terminals 110 and 120, and the core network 300 configured as the IP network is connected to the terminals 110 and 120. It is connected.

In an embodiment of the present invention, the logical functions performed in each network are distributed and accommodated in a transport network based on the Internet protocol. Specifically, the mobile multimedia session control function and the QoS control functions according to an embodiment of the present invention are distributed and accommodated in the network elements of the terminals 110 and 120, the access network 200, and the core network 300. Accordingly, in the case of a mobile multimedia call, a call between terminals 110 and 120 is formed inside an IP-based next generation mobile communication network. In addition, the session establishment and QoS guarantee procedures between the terminals 110 and 120 of the next generation mobile communication network and the server or the terminal existing in the existing external internet network 500 follow the same procedures and methods as those of the existing Internet network.

Looking at the structure of each network, the access network (210,220) is a base station (Radio Station; hereinafter 'RS', 211,221), the gateway (GW, 212,222) and the Access Manager (hereinafter referred to as 'AM', 213, 223).

RS (211,221) performs a wireless connection with the terminal (110, 120), the gateway (212, 222) is connected to the core network (300) Mobile Access Router for routing the access network (210,220) and core network (300); MAR). Thus, hereinafter, gateways 212 and 222 are also referred to as "mobile access routers."

The AMs 213 and 223 are functional elements that perform inherent functions of the mobile communication network, and in particular, manage radio resources and network resources of the access network as well as call state control functions. To this end, the AMs 213 and 223 according to an embodiment of the present invention perform a proxy-call state control function (P-CSCF) 2131 and 2231 (P-CSCF) performing a proxy-call state control function and a policy enforcement force (PEF) that performs a QoS policy execution function. Function, 2132, 2232, and a resource manager (RM, 2133,2233) for managing radio resources and network resources.

The core network 300 includes a Serving-Call State Control Function (S-CSCF) 311 that is in charge of the IP / SDP signaling processing function, and a profile manager 312 which manages subscriber and QoS profiles. The S-CSCF 311 ) Includes a Policy Control Function (PCF) that is responsible for the policy control function.

In such a structure, an agent of a visited network (access network) (P-CSCF) and a home network (core network) serving function (S-CSCF) share and control and process a call state control function (CSCF). In particular, the terminals 110 and 120, the AMs 213 and 223 of the access network, and the S-CSCF 311 and the profile manager 312 mutually engage to negotiate necessary information.

The AM 213 and 223 according to an embodiment of the present invention perform session control to perform QoS control function of the access network according to the decision of the PCF of the core network 300 and the profile manager 312 during QoS control according to the operator's policy. The session and the QoS information of the session obtained during the configuration process are mapped to predetermined resources according to the radio and network resource management states of the resource managers 2133 and 2233 and provided to the gateways 212 and 222, that is, the mobile access routers. Specifically, the AMs 213 and 223 directly control the gateways 212 and 222 using session and QoS information and resource management information, thereby eliminating the QoS negotiation procedure, which is the second step in the session control process described above.

This means that the AM 213 and 223 have a resource management function (RM), a policy enforcement function (PEF), and a proxy-call state control function (P-CSCF), and a function and interface that can control the mobile access router (213, 223). It is possible because it has. The control message transfer between the terminal 110, the AM (213, 223), and the S-CSCF (311) uses a session establishment protocol (SIP).

To this end, the functions of the mobile access routers 212 and 222 and the AMs 213 and 223 in which the mobile communication function and the Internet function are closely combined are defined as described above, and based on these functions, a session for multimedia communication as described below. The setting is made.

Next, a session establishment method according to an embodiment of the present invention will be described based on such a structure.

4 is a flowchart illustrating a session process in a mobile communication network according to an embodiment of the present invention. In particular, FIG. 4 is a diagram illustrating a control signal transmission between elements constituting a network in a mobile communication network according to an exemplary embodiment of the present invention including session control and QoS control network elements.

First, a radio control procedure is performed between the terminal and the RS. That is, through the random access procedure between the RC protocol of the terminal and the RC protocol of the RS, the RS allocates a radio control channel for transmitting a SIP protocol message to the terminal. Then, a session establishment procedure for transmitting the multimedia traffic of the user through the generated radio control channel is performed. According to an embodiment of the present invention, as described below, the end-to-end QoS negotiation is performed together with the session establishment in the session establishment step, thereby simplifying the overall session establishment process.

Specifically, as shown in FIG. 4, first, the terminal 110 transmits an INVITE message, which is a SIP message used when attempting a session connection to the other party, including an SDP, to the access network 210 (S1). Hereinafter, the terminal 110 generating the INVITE message is called a "calling terminal". At this time, the transmitted INVITE message uses the format of the INVITE message (SIP message used when a terminal attempts to connect a session to the other party) described in the existing RFC2543 and RFC3261 as it is, and uses QoS information necessary for session establishment in a wireless section. Contains fields that can be described. These QoS information are used in future QoS negotiation between nodes.

The P-CSCF 2131 of the AM 213 of the access network 210 parses the delivered INVITE message to confirm that the session is a session establishment procedure through exchange of SIP / SDP signals, and then through the gateway 212. Transfer to the core network 300 (S2).

 The S-CSCF 311 of the core network 300 examines the transmitted INVITE message, and the access network to which the originating terminal 110 attempts to connect to the session 120 (hereinafter, referred to as a "terminating terminal") belongs. In operation S3, the terminal 220 checks the INVITE message and confirms the INVITE message to the called terminal access network 220. Therefore, the INVITE message is transmitted to the called terminal 120 through the AM 223 and the gateway 222 of the called terminal access network 220 (S4). In this process, the terminals 110 and 120 and the intermediate nodes 212,222,213,223,311 of each network negotiate resources, and at this time, the session information and QoS information as well as the multimedia codec are transmitted from the originating terminal to the called terminal and related network elements in the route section. Negotiate between (212,222,213,223,311). The negotiation process negotiates what each network element is available for, for example, codec type, flow information (local port number and bandwidth), QoS protocol (ie, RSVP or Diffserv, etc.). By negotiating available resources, the end-to-end available resources are eventually negotiated.

Thereafter, the SDP message corresponding to the SDP is transmitted to the access network 210 and the calling terminal 110 connected thereto in response to the INVITE message through the called terminal 120, the access network 220 and the core network 300. . That is, the session and QoS information negotiated between nodes are transmitted to the calling terminal 110 (S5 to S8). In this case, the QoS negotiation information provided from the access network connected to the called terminal, which is the destination of the INVITE message, may be stored in the SDP message. In addition, when the QoS information requested by the INVITE is changed, the changed QoS information may be included.

Next, a final confirmation process for the negotiated session and QoS information is performed between nodes between the calling terminal 110 and the called terminal 120. That is, a confirmation message (final confirmation SDP message) for the finally confirmed negotiation information is transmitted from the originating terminal 110 to the called terminal 120 through each node 212, 213, 311, 222, and 223 (S9 to S12).

As described above, in order to establish a session for multimedia communication between the calling terminal 110 and the called terminal 120, final confirmation of information negotiated between the nodes 212, 213, 311, 222, and 223 is performed.

Thereafter, the AM 213 of the originating terminal side access network 210 transmits a final acknowledgment SDP message to the S-CSCF 311 of the core network 300, and then sends it to the gateway 212 of the originating access network 210. The operation of the gateway 212 is controlled while transferring the session information, QoS information, and network resource allocation information obtained by performing steps S1 to S12 of FIG.

In addition, the AM 223 of the called side access network 220 also performs the operation while delivering session information, QoS information, and network resource allocation information to the gateway 222 of the called side access network 220, in the same manner as above. It is controlled (S14).

According to this process, the first step for the end-to-end QoS guaranteed mobile multimedia communication, that is, the session establishment and QoS negotiation procedure, is completed, and then the multimedia communication step, which is the second step traffic transmission step, is entered.

As described above, in the embodiment of the present invention, a procedure for negotiating end-to-end QoS (QoS) between a gateway along a traffic path and a terminal of an end is simultaneously performed in a session establishment negotiation step, thereby performing a session establishment process. Is reduced. This is because the mobile multimedia communication procedure, which guarantees end-to-end QoS, is performed in the form of a combination of mobile network elements and Internet network elements. This is because the negotiation process between the related traffic delivery functions is simultaneously performed for the negotiation procedure between the functional elements and the traffic delivery.

Meanwhile, it may be desirable for the traffic forwarding nodes of the core network to become a managed IP network under this concept.

Although the present invention has been described with reference to the most practical and preferred embodiments, the present invention is not limited to the above disclosed embodiments, but also includes various modifications and equivalents within the scope of the following claims.

As described above, according to the embodiment of the present invention, in the IP-based mobile communication system using the SIP, the QoS information transmitted during the session establishment process is used when establishing a session for real-time mobile multimedia communication such as voice and video call. Therefore, the QoS negotiation is performed together with the session establishment, thereby eliminating the general Internet QoS negotiation procedure, which is performed separately, to simplify the mobile multimedia session establishment procedure.

In particular, the access manager of the access network transmits the information obtained during the session establishment and QoS negotiation process to the mobile access router, which is the traffic path, and the mobile access router allocates network resources so that QoS is guaranteed for the session to be set up. In addition, the simplified session establishment procedure and effective end-to-end QoS guarantees multimedia communication.

Claims (7)

An access network connected through a network between a terminal and a core network, the base station being wirelessly connected with the terminal, a gateway connected to the base station to perform routing, and an IP-based mobile including an access manager controlling a network connection through the gateway. In the session establishment method of the communication system, (a) setting a radio control channel through which the base station transmits a message according to a service request of the terminal; (b) the base station receives a session establishment request from the terminal through the established radio control channel, and exchanges a message between the terminal and a serving-call session control function (S-CSCF) of the core network through the gateway; Simultaneously performing a session control procedure and resource allocation and quality of service (QoS) negotiation of the radio section; And c) allowing the access manager to control the operation of the gateway so that traffic is transmitted to the terminal based on the session information, QoS information, and resource allocation information obtained by performing the session control procedure. Session establishment method of an IP-based mobile communication system comprising a. The method of claim 1 Step b) Receiving, by the access manager, an INVITE message from the terminal through the established radio control channel, wherein the INVITE message includes QoS information necessary for establishing a session of a radio segment; The access manager parsing the INVITE message to extract QoS information, and transmitting the received INVITE message to the S-CSCF of the core network; An SDP message in which the access manager responds to an INVITE message from the terminal from the S-CSCF, wherein the SDP message stores QoS negotiation information provided from an access network connected to a destination terminal that is a destination of the INVITE message; Receiving and transmitting to the terminal; And The access manager receiving a final acknowledgment message for the SDP message from the terminal and transmitting the final acknowledgment message to the S-CSCF of the core network to perform a final acknowledgment of the negotiated information; Session establishment method of an IP-based mobile communication system comprising a. The method according to claim 1 or 2 In step c), the access manager allocates a predetermined resource to the gateway according to the negotiated QoS information based on a network resource management state, so that traffic is transmitted to the terminal through the resource. How to establish sessions on your system. The method of claim 2, If the QoS information required in the INVITE message is changed, the session establishment method of the IP-based mobile communication system including the changed QoS information in the SDP message. In the IP-based mobile communication system connected between the mobile terminal and the core network through a network, A gateway connected to a base station connected to the mobile communication terminal to perform routing; And Receives a session establishment request from the terminal and exchanges messages between the terminal and a Serving-Call Session Control Function (S-CSCF) of the core network through the gateway to perform session control procedures, resource allocation, and QoS negotiation between radio sections. The access manager so that it runs concurrently IP-based mobile communication system comprising a. The method of claim 5 The access manager A resource manager to manage radio resources and network resources; A proxy-call state control function (P-CSCF) for controlling a call state for a terminal connected through the base station and performing a session establishment function by performing a message exchange according to the session establishment request; And Policy Enforcement Function (PEF) that performs QoS policy execution function by interworking with S-CSCF of core network based on the radio resource and network resource management status IP-based mobile communication system comprising a. The method according to claim 5 or 6 The first message according to the session establishment request transmitted from the terminal is in the form of a SIP message, includes QoS information necessary for establishing a session in a wireless section, and from the S-CSCF of the core network in response to the first message. The second message transmitted is stored in the QoS negotiation information provided from the access network connected to the destination terminal that is the destination of the first message.

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