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QOS SUPPORT METHOD IN A HIGH-RATE
PACKET DATA SYSTEM
This application claims the benefit under 35 U.S.C. § 119(a) to an application entitled "QoS Support Method in a High-Rate Packet Data System" filed in the Korean Intellectual Property Office on Oct. 30, 2003 and assigned Serial No. 2003-76386, the entire contents of which are incorpo- 10 rated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention 15 The present invention relates generally to a Quality-of
Service (QoS) support method in a high-rate packet data system. In particular, the present invention relates to a method for providing QoS information to an access network.
2. Description of the Related Art 20 A Code Division Multiple Access 2000 (CDMA2000)
system has been developed from an Interim Standard-95 (IS-95) system for chiefly supporting transmission and reception of voice signals into IS-2000 and IS-856 systems capable of transmitting and receiving high-rate data as well 25 as voice signals. In particular, CDMA2000 lx and lxEVDO systems provide a function of transferring data on a packet-by-packet basis.
A communication scheme such as an existing telephone service secures a path through a previous signaling proce- 30 dure with the desired party. The secured path cannot be used by other users. By transferring data through the designated path, it is possible to prevent a possible delay in a transmission section.
In the Internet Protocol (IP)-based packet communication 35 architecture, data is transmitted with a header attached to the head thereof, instead of being transmitted after a path is previously set up, and routers forward the data to its destination based on the header information. Furthermore, in the IP-based packet communication architecture, when there is 40 a large volume of traffic, data is transmitted in arrival order. Such a scheme for transmitting data in arrival order regardless of its traffic type is called a "Best Effort."
The current scheme for transferring a packet via a CDMA2000 packet network is achieved by the Best Effort 45 scheme. Such a data transfer scheme cannot guarantee transmission of real-time data for packet-based Video Telephone Service and packet-based Packet Voice Service (known as VoIP Service), for example, which will be introduced in the future. In addition, even such a data service 50 which is insusceptible to a transmission delay is provided in different Quality of Service levels (QoSs) according to conditions of a network, thus causing users dissatisfaction. That is, the packet-based data transmission architecture disadvantageously cannot guarantee QoS in transmission of 55 real-time data.
A QoS Support scheme for packet transmission has been introduced as a scheme for resolving such a problem.
The QoS Support scheme can be classified into an IP QoS Support scheme defined in a network layer in a CDMA2000 60 network, and a QoS scheme in an access network corresponding to a lower layer for supporting the IP QoS Support scheme. The IP QoS scheme has been mostly standardized by the Internet Engineering Task Force (IETF), an international standardization organization, and includes an Inte- 65 grated-Service (Int-Serv) scheme and a Differentiated-Service (Diff-Serv) scheme as typical schemes.
In the Int-Serv scheme, each node desiring to transmit data sets up the necessary resources through a previous reservation procedure before transmitting data, and a Resource reSerVation Protocol (RSVP) is used as a signaling protocol for resource reservation.
In the Diff-Serve scheme, each node desiring to transmit data designates relative priority for a packet in a data header before transmission, thereby differentially processing a packet based on priority information acquired through the header.
Such an IP QoS Support method is available in an IP node. In a CDMA2000 network, the IP QoS Support method can be applied to access terminals (ATs), a packet data service node (PDSN), and several routers constituting an IP core network.
A CDMA2000 Access Network QoS scheme provides a QoS function between an access network and an access terminal, and can provide the QoS function through QoS parameters defined in an access network and a control algorithm. Therefore, in order to support an End-to-End QoS scheme, interworking between a standardized IP QoS scheme and a QoS scheme in an access network is needed. In the current 3rd Generation Partnership Project 2 (3GPP2), for End-to-End QoS Service, QoS of an access network is set between an access terminal and a packet data service node (PDSN) by transferring QoS information through RSVP, and a packet data network after the PDSN considers supporting Relative QoS by Diff-Serv.
FIG. 1 is a diagram illustrating an architecture for supporting End-to-End QoS via a CDMA2000 packet network whose standardization is currently in progress. Referring to FIG. 1, an upper application layer can acquire required QoS information by exchanging information for session setup (106), and can support IP QoS Service (107) capable of performing relative packet processing by actually reserving required resources through End-to-End QoS information transmission in an IP layer or setting a DiffServ Code Point (DSCP) value in an IP header. Such a QoS Support scheme in an IP layer must interwork with a QoS setup method (108) in an access network (AN) 102 that supports actual Bearer Service. That is, IP QoS Service (107) is a scheme that can be used between nodes performing IP communication, and a CDMA2000 packet network corresponds to an access terminal (AT) 101, a PDSN 103, and routers constituting an IP core network. The access network (AN) 102 constituting a CDMA2000 access network is not an IP node, and it supports QoS by a QoS scheme defined in a separate access network 102. Therefore, an algorithm for interworking between IP QoS and CDMA2000 Access Network QoS is required, and QoS parameters for the algorithm must be defined.
In the current CDMA2000 lx system, it is possible for an access terminal to transfer a QoS BLock-of-Bits (BLOB) representative of QoS information to a network. However, the CDMA2000 lxEV-DO system does not support a method in which an access terminal transfers a QoS BLOB representative of QoS information to a network.
In the CDMA2000 1 x system, because multiple services can be distinguished using service option information, separate QoSs can be managed for separate services. However, currently, the CDMA2000 lxEV-DO system does not provide a scheme for distinguishing multiple services. Therefore, a scheme for performing separate QoSs for separate services and a scheme for distinguishing multiple services are required.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method for enabling a QoS function by setting up traffic so that it corresponds to a service characteristic 5 provided in a mobile communication system.
It is another object of the present invention to provide a mapping method for interworking between an IP QoS scheme and an Access Network QoS scheme.
To achieve the above and other objects, there is provided 10 a Quality-of-Service (QoS) Support method in a mobile communication system including an access terminal, an access network for performing packet data communication with the access terminal, a packet control function for controlling transmission and reception of packet data 15 between the access network and the access terminal, and a packet data service node for exchanging packet data with the packet control function. In the method, the access terminal maps a requirement based on an application characteristic to an Internet Protocol (IP) QoS parameter, generates a 20 resource reservation protocol (RSVP) message, and transmits the resource reservation protocol message to the packet data service node. The packet data service node maps IP QoS information to be transmitted to the access terminal to QoS information needed in the access network, and trans- 25 mits the mapping result to the access network via the packet control function. The access terminal receives data including QoS information from the packet data service node, and performs communication according to the QoS information.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction 35 with the accompanying drawings in which:
FIG. 1 is a diagram illustrating architecture for supporting End-to-End QoS via a CDMA2000 packet network whose standardization is currently in progress;
FIG. 2 is a diagram illustrating a mobile communication system to which an embodiment of the present invention is applied;
FIG. 3 is a message flow diagram illustrating a method for transmitting QoS information according to an embodiment 45 of the present invention; and
FIG. 4 is a flowchart illustrating a method for mapping QoS information in a packet data service node according to an embodiment of the present invention.
Throughout the drawings, like numbers are used to refer 50 to like features and structures.
DETAILED DESCRIPTION OF THE
A preferred embodiment of the present invention will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for conciseness. 60
The present invention provides a method for transferring QoS mapping information to a network through an RSVP message according to an application characteristic in a high-rate packet data system, mapping the QoS mapping information to an Access Network QoS parameter in a 65 packet data service node, and transferring the mapping result to a lower layer.
When there are multiple services, QoSs are separately applied to the services by transferring information for distinguishing the services from a packet data service node to an access network.
FIG. 2 is a diagram illustrating a mobile communication system for implementing an embodiment of the present invention. Referring to FIG. 2, the mobile communication system includes an access terminal (AT, or a mobile station (MS)) 210, access network controllers (ANCs, or base station controllers (BSCs)) 220a and 2206 for controlling access network transceivers (ANTSs, or base transceiver subsystems (BTSs)) and an access network transceiver, both in radio communication with the access terminal 210. The mobile communication system also includes a packet data service node (PDSN) 240, packet control functions (PCFs) 230a and 2306 connected between the packet data service node 240 and the access network controllers 220a and 220b for performing packet data communication, an Authentication, Authorization and Accounting (AAA) server 280 for controlling service authentication and accounting, border routers (BRs) 250a and 2506 for connecting an access network 220 to an IP core network 260, and a correspondent node (CN) 270 for indicating an End-to-End (E2E) QoS Support coverage with the access terminal 210.
The access terminal 210 performs a CDMA2000 radio connection function with the access network (220a or 2206), and is connected to the packet data service node 240 through a Point-to-Point Protocol (PPP) link layer connection. The access terminal 210, located in an end for E2E QoS service, performs an E2E QoS signal processing function between ends, performs a function of mapping application QoS requirements to IP QoS parameters, and transmits the mapped QoS information to the CN 270 through RSVP. The packet data service node 240 sets up a QoS bearer in a CDMA2000 access network section based on the information. Further, the access terminal 210 supports Multiple Service Instance (MSI), and therethrough, provides a QoS function through radio traffic setup corresponding to an application characteristic.
The access network 220a, 2206 provides a CDMA2000 radio connection function with the access terminal 210, and provides a packet data service with the packet data service node 240 through a Layer-2 connection (or R-P connection) function. The access network 220a, 2206 sets up a bearer for QoS Support in an access network section based on QoS information received from the packet data service node 240. In the access network section, QoS provides a resource management function in an access network and radio section, a QoS admission control function, a congestion control function between internal nodes of the access network 220a, 2206, and a radio frequency (RF) scheduling function. QoS also provides a QoS function corresponding to a traffic characteristic of an application through MSI resource together with the access terminal 210.
The packet data service node 240 is connected to the access network 220a, 2206 through an R-P connection, and provides a PPP connection to the access terminal 210 through the R-P connection (RAN-PDSN connection) and a packet data service therethrough. The packet data service node 240, through interworking with the AAA server 280, acquires a QoS profile for each access terminal and performs a QoS authentication function based on the QoS profile upon
function for IP QoS Service, and provides Metering, Classification, Shaping and Dropping, and Marking functions for the Diff-Serv Edge function.
The BRs 250a and 2506 are routers for providing a gateway function so as to enable the CDMA2000 network including the access networks 220a and 220b and the core network to interwork with an external network (Internet or another service provider's network), and performs an IP packet routing function defined in the IETF standard. The BR 250a or 2506 can perform a Re-marking function according to a Service Level Agreement (SLA) and a Traffic Conditioning Agreement (TCA) for transmission and reception of packets for QoS Service.
The CN 270 manages a network element (NE) corresponding to a counterpart node with which the access terminal desires to communicate, and can be an access terminal in the CDMA2000 network or a server in the Internet. In one embodiment of the present invention, the CN 270 is functionally identical to the access terminal 210.
FIG. 3 is a message flow diagram illustrating a QoS Support method in the mobile communication system according to an embodiment of the present invention. Referring to FIG. 3, in step 400, an access terminal 210 maps a requirement based on an application characteristic to an IP QoS parameter. In step 410, the access terminal 210 transmits the mapped IP QoS parameter to a packet data service node 240 through an RSVP message.
In step 420, the packet data service node 240 maps the IP QoS parameter received in step 410 to an AN QoS parameter, for QoS information to be used during traffic setup in an access network 220. In step 430, the packet data service node 240 includes the AN QoS parameter in a Normal
50 Referring to Table 2, traffic class information can be written, and in an embodiment of the present invention, a service class is classified into the following four service classes.
55 The service class is classified into a Conversational class, a Streaming class, an Interactive class, and a Background class. The respective service classes have their own requirements for a packet loss, a delay, and a bandwidth. A method for mapping an IP QoS parameter to an Access Network
60 QoS parameter of the packet control function 230 in step 420 will be described in detail herein below.
In step 440, the packet control function 230 receiving the QoS information transmits the QoS information to the
65 access network 220 through an A9-Update-A8 message. An example of the A9-Update-A8 message is illustrated in Table 3.
to the packet control function 230 to acknowledge successful receipt of the QoS information.
In step 460, the packet control function 230 transmits an All -Session Update Ack message to the packet data service node 240 to inform the packet data service node 240 of successful transmission of the QoS information.
In step 470, the access terminal 210 receives data from the packet data service node 240 based on the QoS information transmitted in step 400.
A detailed description will now be made of a method for mapping IP QoS information to a QoS parameter for QoS setup of the access network, performed in step 420, and a method for defining the QoS parameter transmitted through the mapping.
An Access Network QoS parameter for transferring an IP QoS parameter acquired through IP QoS to an access network through mapping is classified into an AN Traffic Class parameter and a Bandwidth parameter.
In 3GPP2, all traffics are classified into four traffic classes according to their characteristic as shown in Table 4. The traffic classes are fundamentally classified according to Delay, Delay Variation, and Information Loss in terms of application.
Because the access network 220 needs to subdivide the traffic classes, an embodiment of the present invention classifies a traffic class for the access network 220 into 7
50 traffic classes illustrated in Table 5. A first criterion for the classification shown in Table 5 considers a characteristic of a radio section, and each traffic class is subdivided into two traffic classes according to whether Radio Link Protocol (RLP) is necessary in a radio link for which a characteristic
55 of information loss is considered. Here, Background class, which is not for QoS traffic, is not separately divided. A second criterion classifies priority in terms of a transmission delay, which is most keenly required for QoS. The priority is determined in order of Transmission Delay and Delay