WO2005009065A1

WO2005009065A1 - A method for improving service quality in universal mobile telecomunications system (umts) radio

Info

Publication number: WO2005009065A1
Application number: PCT/CN2003/000575
Authority: WO
Inventors: Sheng Liu; Baijun Zhao; Jun Hu
Original assignee: Utstarcom (China) Co., Ltd.
Priority date: 2003-07-17
Filing date: 2003-07-17
Publication date: 2005-01-27
Also published as: CN1788514A; AU2003252519A1; CN100421500C

Abstract

The present invention provides a method for improving service quality in Universal Mobile telecommunications System (UMTS) radio access network, therein said Universal Mobile telecommunications System includes: core net, one or more UMTS terrestrial radio access networks and many user equipment (UE), therein core net is divided into Circuit Switching (CS) field and Packet Switching (PS) field, said PS field communicates with UTRAN by Iu-PS interface; said UTRAN communicates with one or more UE by Uu interface, every said UTRAN includes many radio network controllers (RNC); and one or more Node B which communicates with said RNC by lub interface, every Node B includes one or more cells, and that RNC communicates by lur interface, said method comprising the following steps of: distinguish service code point (DSCP) value from Iu-PS core net badge in down-link is used in UTRAN inner switching’s classify, controlling and distinguish service operator. The present invention makes use of DSCP from lu-PS core net badge to realize improving Qos further.

Description

Universal mobile communication system

Method for improving service quality in radio access network

The present invention relates to a method for implementing improved QoS in a UMTS radio access network (UTRAN). Background technique

The UMTS (Universal Mobile Telecommunications System) system is a third-generation mobile communication system that uses WCDMA as a wireless technology. Its standardization work is completed by the 3GPP organization. So far, there are four versions, which are known as Release 99, Release 4, and Release 5. And Release 6. The R5 version is the first version of all IP (or full packetization). Improvements in the radio access network include the following aspects. A high-speed downlink packet access HSDPA technology is proposed, which enables the downlink rate to reach 8-10Mbps, which greatly improves The efficiency of the air interface is increased; the Iu, Iur, and Iub interfaces add an optional transmission method based on IP, so that the wireless access network is IP-based.

In the UMTS (Universal Mobile Telecommunications System) network system structure shown in FIG. 1, the core network (CN) 1 is connected to the UTRAN (radio access network) 2 through the Iu interface, and the UTRAN 2 is connected to the UE (user equipment) through the Uu interface. 3 are connected. Figure 2 further shows the network structure of UTRAN, where the radio network controller (RNC) 4 is connected to the core network 1 through an Iu interface, RC 4 is connected through an Iur interface, and one RC 4 is connected to one or more nodes B 5 (node B) is connected through the Iub interface. A Node B 5 contains one or more cells 6, and the cell 6 is the basic unit of UE radio access.

In the UMTS system of R99, the core network is divided into a circuit-switched (CS) domain and a packet-switched (; S) domain. Figure 3 further illustrates the end-to-end structure of the PS domain UMTS network. MT 12 and TE 11 in the figure respectively represent mobile terminals and terminals. Equipment, SGSN (Serving GPRS Support Node) 14 and GGSN (Gateway GPRS Support Node) 15 are network elements of the PS domain core network. The interface between them is the Gn interface, the interface between SGSN14 and UTRAN13 is the Iu-PS interface, and GGSN15 The interface with the UMTS network external packet data network (PDN) 16 is a Gi interface. In the R99 UMTS system, the architecture of the PS domain core network is an IP (Internet Protocol) based packet switching network. In the R4 / R5 UMTS system, the core network has further evolved into an all-IP architecture. Since the IP network is characterized by providing "best effort" services, how to ensure the quality of service (QoS) of users has become a key issue in the UMTS network.

In the standard TS23.107 of the 3GPP (笫 3 Generation Cooperative Project), the QoS structure of UMTS is defined, as shown in Figure 4. The UMTS bearer service in the figure is composed of two segments: the radio access bearer (RAB) service and the core network bearer service, and the radio access bearer service is composed of the radio bearer service and the Iu bearer service. According to TS23.107, Iu bearer services and core network bearer services can use differentiated services (DiffServ) to achieve QoS. For wireless bearer services, QoS requirements are implemented in wireless interface protocols.

UMTS bearer service QoS is implemented based on the PDP Context (packet data protocol context) and its included QoS attribute parameters. PDP Context is a general term for all relevant information sets of a UE during a session. It includes QoS attribute parameters, PDP type, PDP address assigned to the UE (that is, IP address for IP networks), and a gateway (ie, GGSN) connected to an external PDN. And other information. A PDP

Context corresponds to a UMTS bearer service. UMTS supports multiple PDP contexts using the same PDP address. Each PDP context can have different QoS requirements. In order to distinguish the PDP Context groupings with different QoS requirements for the same PDP address, the TFT (Service Flow Template) technology is used in UMTS.

TFT is a set of grouping filters, which can be distinguished by DiffServ code points, IPv6 traffic tags, IP source addresses, etc .; each PDP context of a PDP address Grouping. The TFT is generated and managed by the UE, where the TFT in the uplink direction is in the UE and the GGSN in the downlink direction (transmitted from the UE to the GGSN by the PDP Context activation or modification process).

FIG. 5 is a schematic diagram of a UMTS bearer service QoS establishment process initiated by ΕΕ3. When an application in UE3 wants to initiate a session, it causes the lower layer to initiate a request to activate the PDP Context to the SGSN14 through an API (Application Programming Interface) interface.

(Step S1), the corresponding message carries the QoS attribute parameters required by the application. If a PDP Context with the same PDP address already exists, the corresponding message also includes a TFT for GGSN to classify the downlink packet. In the SGSN / GGSN, the resources required for the core network bearer will be allocated according to the QoS attribute parameters. In addition, the QoS parameters of the PDP Context will be mapped to the DSCP (DiffServ code point) value in the backbone network (if the backbone network uses DiffServ to provide QoS guarantee), and QoS parameters of the RAB (step S2). Then the SGSN14 initiates an RAB allocation command to the RNC4 (step S3), and the RNC4 further establishes an Iu bearer and a radio bearer according to the RAB QoS parameters provided by the SGSN14 (step S4). In this way, an UMTS bearer for an application of the UE is established in the UMTS network.

In order to further clarify the method proposed by the present invention, the differentiated service-based QoS technology used in the IP network will be briefly introduced below. The IP QoS proposed by the Internet Engineering Task Force (IETF) mainly includes integrated services (IntServ) and differentiated services

(DiffServ) Two categories, of which DiffServ is considered to be the most promising technology for solving QoS problems in IP networks due to its good expansion performance. As mentioned earlier, in UMTS, Iu bearer services and core network bearer services also mainly adopt DiffServ to implement QoS. In DiffServ technology, the edge nodes of a network classify packets and mark the DSCP. The "hop-by-hop behavior" (PHB) in classifying and forwarding packets by intermediate nodes is determined by the DSCP. In an IP network, the domain used by DSCP is the TOS (Service Type) domain in the IP header in IPv4, and the Traffic Class domain in the IP header in IPv6. In DiffServ, PHBs are divided into three types: best effort (BE) PHB, fast forwarding (EF) PHB, and ensured forwarding (AF) PHB, as shown in FIG. Among them, BE PHB packets do not need to be specially processed, so they try their best to deliver services. Packets marked with EF should be forwarded with minimum delay and the packet loss rate should also be low. AF PHB is subdivided into several subclasses, which is represented by AFxy. Where X is the AIV category, and different queues are assigned to the packets accordingly, and y represents the drop priority of the packet. AF packets of the same category, that is, the same X, enter the same queue. When network congestion needs to be discarded, the lower the discarding priority in the same queue, that is, the packet with a larger y value is discarded first.

According to TS23.107, UMTS services are divided into four QoS categories, namely session type, stream type, interaction type, and background type. For each service type, multiple parameters reflecting QoS attributes are defined, as shown in Figure 7. As shown. As previously mentioned, during the establishment of the UMTS bearer service, the QoS parameters of the PDP Context are mapped to DSCP values in the DiffServ-based backbone network. 3GPP does not define a specific mapping scheme for this, but leaves it to the operator to configure it according to its network configuration, operation strategy, and so on. Figure 8 shows the mapping relationship between a typical DiffServ PHB type and a UMTS service type. As shown in FIG. 8, since the AF PHB type of DiffServ is relatively fine-divided, UMTS services mapped as AF can also be subdivided into different QoS attribute parameters such as transmission delay and service processing priority. AF category.

Figure 9 shows the structure of the user plane protocol stack in R99. For a detailed description of the user plane protocol GTP-U / UDP / IP in the PS domain, you can refer to the TS23.060, TS29.060 and other protocols of 3GPP. About Wireless For detailed description of the interface user plane protocol PDCP / RLC / MAC, please refer to 3GPP's TS25.301, TS25.321, TS25.322, TS25.323 and other protocols; About the Iu-PS interface user plane protocol GTP-U / UDP / For IP / AAL5 / ATM, refer to 3GPP's TS25.410, TS25.414, TS25.415, TS29.060 and other protocols. In FIG. 9, the IP layer marked “*” indicates a DSCP mark with DiffServ. It should be noted that the IP layer in FIG. 9 DiffServ is only exemplary, and does not exclude other transmission technologies to ensure QoS. For example, MPLS (Multi-Protocol Label Switching) or a combination of MPLS and DiffServ can be used. When MPLS is used, FEC (Forwarding Equivalence Class) of different QoS can be distinguished by MPLS label value. When the technology combining MPLS and DiffServ is used, the EXP field of MPLS can be used to mark the DSCP value of DiffServ.

In the upstream direction, if there are multiple PDP Contexts with the same PDP address, the ϋ classifies packets with different QoS from the application according to the TFT, and transmits them to the RNC using wireless bearers of different wireless interfaces. Depending on the specific implementation, it can be determined by The RC or SGSN marks the uplink packet of the UE in accordance with the known QoS attribute parameters of each RAB and certain mapping rules to mark the DSCP value of the uplink direction GTP-U / UDP / IP. When the upstream packet reaches the GGSN, the GGSN can also map the DSCP on the GTP-U / UDIVIP to the DSCP value corresponding to the packet sent to the PDN carried in the GTP-U tunnel. In the downstream direction, if there are multiple PDP contexts with the same PDP address, the GGSN will use the downlink TFT to classify packets from external PDNs, group FDP contexts with different QoS requirements, and according to known QoS attributes of each UMTS bearer service Information such as parameters and certain mapping rules mark the DSCP value of GTP-U / UDP / IP in the downlink direction. When the downlink packet reaches the RNC, the RNC uses the RAB corresponding to the GTP-U tunnel of the Iu-PS interface to change the downlink direction. The packet is transmitted to the UE through the wireless interface.

According to the previous analysis, two types of QoS-related information can be obtained in the RNC, namely, the QoS attribute parameters of the RAB provided by the SGSN during the RAB establishment or modification process, and the DSCP value of the core network tag from the Iu-PS, where The DSCP value marked by the core network from the Iu-PS only reflects the QoS information of the UMTS bearer service in the downlink direction. In the above two types of QoS-related information, the QoS attribute parameter of the RAB provided by the SGSN during the RAB establishment or modification process is static. Unless the RAB is modified, the parameter will not change throughout the RAB's lifetime. The DSCP value of the core network tag from the Iu-PS is dynamic, because the GGSN's marking of the DSCP value of the GTP-U / UDP / IP packet in the downlink direction depends not only on the QoS attributes of the UMTS bearer service, but also according to the specific implementation. It may also depend on other factors, for example, the GGSN may dynamically adjust the mapping rules of QoS attributes and DSCP values of UMTS bearer services according to parameters such as the congestion status of the core network. Therefore, the DSCP value of the core network tag from the Iu-PS in the downlink direction can better reflect the QoS characteristics of the UMTS bearer service. In fact, even if a UMTS bearer service has a higher QoS priority, if congestion occurs in the core network at a certain moment, it will not be appropriate to assign a higher priority to the service in the radio access network because this Some packets of the service may have been discarded in the core network, or a large delay may have occurred. Assigning a higher priority to the service in the radio access network will cause waste of wireless resources.

As mentioned earlier, when the RNC establishes or modifies an RAB, according to the QoS attribute parameters of the RAB provided by the SGSN, configure the corresponding radio parameters to create a radio bearer that meets its QoS requirements. However, during the lifetime of the RAB, due to changes in radio resources and services in the RA, the QoS-related information of the RAB still needs to be used to further optimize the QoS. Because in the downlink direction, the DSOP value of the core network tag from the Iu-PS can better reflect the QoS dynamic characteristics of the UMTS bearer service, the present invention proposes to implement the improvement in the UMTS radio access network (UTRAN) based on this. QoS method. Summary of the invention

According to the present invention, a method for improving quality of service in a Universal Mobile Telecommunications System (UMTS) radio access network is provided herein, wherein the universal mobile communication system includes: a core network, one or more universal mobile communication systems wireless access Network Access (UTRAN) and multiple user equipment (UE), where the core network is divided into a circuit switched (CS) domain and a packet switched (PS) domain, and the PS domain is through an Iu-PS interface Communicate with UTRAN; the UTRAN communicates with one or more peers through a Uu interface, each UTRAN includes multiple Radio Network Controllers (RNCs); and one or more Node Bs that communicate with the RNC through an Iub interface Each Node B includes one or more cells, and the RNC communicates through the Iur interface. The method includes the following steps: In a downlink direction, a differentiated service code point (DSCP) value marked by the core network from the Iu-PS An operation applied to the classification, scheduling, or differentiated services of UTRAN internal packets.

According to an aspect of the present invention, in a Universal Mobile Telecommunications System (UMTS) radio access network, before the GTP-U processing module from the RNC side of the downlink Iu-PS interface in the RC, according to the Differentiate the service code point (DSCP) value to classify the IP packets processed by AAL5 / ATM; make the classified IP packets enter the IP packet queues of different priorities; and output the IP packets according to the IP packet scheduling method.

According to another aspect of the present invention, in a Universal Mobile Telecommunications System (UMTS) radio access network, in the downlink direction, media access control (MAC) layer packet scheduling for a common transmission channel or a shared channel uses Iu-PS from The DSCP value marked by the core network, or combine this parameter with the QoS attribute parameters of the RAB provided by the SGSN during the RAB establishment or modification process, or further combine the relevant parameters reflecting the current wireless resource status to determine the Priority; applying the determined priority of each channel to the transport format combination set selection method; and outputting the MAC layer packetization degree.

According to another aspect of the present invention, in a Universal Mobile Telecommunications System (UMTS) radio access network, the RNC is based on the DSCP value marked by the core network from the Iu-PS, or the parameter is used in the RAB establishment or modification process. Combine the QoS attribute parameters of the RAB provided by the SGSN, or further combine the current wireless resource-related information to classify the IP packets sent from the Iur / Iub interface; mark the DSCP value according to a predetermined rule; output the IP differentiated service packet to Ensure service in the downward direction Quality of Service (QoS).

Since the distinguished good service code point (DSCP) value of the core network tag from the Iu-PS better reflects the QoS dynamic characteristics of the corresponding UMTS bearer service, the present invention utilizes the core network tag from the Iu-PS in the downlink direction. DSC value, and further optimize the QoS. It should be noted that although the present invention describes the three operations of the above fans as specific applications, the present invention is not limited to the above three operations, that is, according to the present invention, the DSCP value of the core network tag from the Iu-PS can be separated Or in combination with the QoS attribute parameters of the RAB provided by the SGSN during the RAB establishment or modification process, it is applied to the occasion where the QoS related information of the RAB is required in UTRAN, so as to achieve further optimization of the QoS. BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter, preferred embodiments of the present invention will be described by way of example with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the structure of a UMTS (Universal Mobile Telecommunications System) network system;

FIG. 2 is a schematic diagram showing a network structure of UTRAN;

Figure 3 is a schematic diagram of the end-to-end structure of a PS domain UMTS network;

Figure 4 is a schematic diagram showing the UMTS bearer service QoS architecture; Figure 5 is a diagram showing the establishment of a UMTS bearer service to ensure QoS; Figure 6 shows the recommended DSCP value of the standard PHB in DiffServ;

FIG. 7 shows QoS attribute parameters of a UMTS bearer service;

FIG. 8 shows a mapping relationship between a typical DiffServ PHB type and a UMTS service type;

FIG. 9 is a schematic diagram showing the structure of a user plane protocol stack in R99;

FIG. 10 is a schematic diagram showing an IP packet queue in front of a GTP-U processing unit on the RNC side of a downlink Iu-PS interface according to the present invention;

FIG. 11 illustrates a downlink common transmission channel / shared channel according to the present invention MAC layer packet scheduling;

FIG. 12 shows the classification and DSCP marking of IP packets in the IP RAN downlink direction according to the present invention. detailed description

As one of the specific embodiments of the present invention, before the GTP-U processing module from the RNC side of the downstream Iu-PS interface in the RNC, according to the DSCP value of the core network tag from the Iu-PS, the IP after AAL5 / ATM processing is processed. The packets are classified to support IP packet queues of different priorities.

As shown in FIG. 10, in the RNC, after the data from the Iu-PS passes through the AAL5 / ATM processing unit, the GTP-U / UDP / IP packet is obtained (step S10), so it can be classified according to its DSCP value (step S11), respectively, into IP packet queues of different priorities (step S12), and based on a certain IP packet scheduling method (step S13), output to the GTP-U processing unit (step S14). In this way, IP packet queues with different priorities based on DSCP can better guarantee the QoS of services with different priorities. Among them, the IP packet scheduling may adopt an existing technology, typically such as a WFQ (Weighted Fair Queue) scheduling method, etc. In addition, an existing queue management technology such as RED (Random Early Detection) may be used to prevent queue congestion, etc. .

As one of the specific embodiments of the present invention, in the MAC (Media Access Control) layer packet scheduling of the common transmission channel or shared channel in the downlink direction, the DSCP value marked by the core network from the Iu-PS is used, or The RAB's QoS attribute parameters provided by the SGSN during RAB establishment or modification are combined or further combined with radio resource related information to determine the priority of each logical channel.

The downlink common transmission channel in UMTS is FACH (forward access channel), and the downlink shared channels include DSCH (shared channel), HS-DSCH (high-speed shared channel), and so on. Since different logical channels of different UEs share a certain transmission channel bandwidth, an effective MAC layer packet scheduling mechanism is the key to ensuring the QoS of each UE. The MAC layer packet scheduling is based on optimizing the use of wireless resources while ensuring the priority and fairness of each RAB service. FIG. 11 is a schematic diagram of a downlink common transmission channel packet scheduling unit. First, packets from different logical channels (S20) enter the corresponding logical channel packet queue (S21), queue scheduling and TFC (Transport Format Combination Set) selection unit. (S22) According to a certain algorithm, a packet to be sent and a corresponding TFC (S24) are scheduled to be output at each transmission time interval (TTI). Among them, in order to ensure QoS, the queue scheduling and TFC selection unit needs to consider the priority of each logical channel reflecting QoS requirements as input parameters. In addition, relevant parameters reflecting the current wireless resource status may be further used as input parameters of the unit, and queue scheduling And the method selected by TFC, as mentioned above, while ensuring the priority and fairness of each RAB service, the use of wireless resources should be optimized, and the specific algorithm can adopt the relevant methods in the prior art. According to the present invention, the DSCP value from the core network tag of the Iu-PS that reflects the QoS information of RAB of different UEs is used, or the parameter is combined with the QoS attribute parameter of the RAB provided by the SGSN during the RAB establishment or modification process, Determine the priority of each channel (S23). Among the priorities, relevant parameters reflecting the current radio resource status depend on specific methods, such as the required transmit power, downlink interference, etc. mentioned in the patent application with publication number US2003 / 0099249 A1.

As one of the specific embodiments of the present invention, when the Iub / Iur interface of the UTRAN adopts the IP RAN architecture based on IP transmission, the DSCP value marked by the core network from the Iu-PS is used, or the parameter is used in the RAB establishment or modification process. The QoS attribute parameters of the RAB provided by the SGSN are combined, or further combined with the current radio resource status of the RAB, to classify the transport network layer IP packets in the downstream direction and map them to the corresponding DiffServ code points to provide QoS guarantee.

The IP RA architecture based on IP transmission is in line with the development direction of UMTS of all IP. Since IP transmission is used, how to ensure QoS is its first problem. According to the present invention, as shown in FIG. 12, in the downlink direction, the RNC The DSCP value marked by the core network, or the parameter is combined with the QoS attribute parameters of the RAB provided by the SGSN during the RAB establishment or modification process, or further combined with the current radio resource status (the specific parameters used, as described above, depends on Based on a specific method), classify the IP packets sent from the Iur / Iub interface (S30), mark 08 <: 1 »values (S31) according to certain rules, and output IP DiffServ packets (S32) to ensure downlink Directional QoS. Although the principle of the present invention has been described in detail above with reference to specific embodiments, the scope of the present invention is limited only by the appended claims, and is not limited to these specific embodiments. Those of ordinary skill in the art can follow the spirit of the present invention. Various changes and modifications are made, and these changes and modifications are included in the scope of the present invention.

Claims

1. A method for improving service quality in a universal mobile communication system (UMTS) radio access network, wherein the universal mobile communication system includes: a core network, one or more universal mobile communication system radio access networks (UTRAN) And multiple user equipments (UEs), where the core network is divided into a circuit switched (CS) domain and a packet switched (PS) domain, the PS domain communicates with the UTRAN through an Iu-PS interface; and the UTRAN communicates with a UTRAN through a Uu interface Or multiple UEs communicate, each UTRAN includes multiple radio network controllers (RCs); and one or more Node Bs that communicate with the RNC through an Iub interface, each Node B includes one or more cells, The RNC communicates through an Iur interface, and the method includes the following steps:

In the downlink direction, the differentiated service code point (DSCP) value marked by the core network from the Iu-PS is applied to the classification, scheduling, or differentiated service operation of the UTRAN internal packet.

2. The method according to claim 1, further comprising the step of: before the GTP-U processing module on the RNC side from the Iu-PS interface in the downlink direction in the RNC, distinguishing services according to the core network tag from the Iu-PS Code point (DSCP) value to classify the IP packets after AAL5 / ATM processing; make the classified IP packets enter the IP packet queues of different priorities; and output the IP packets according to the IP packet scheduling method.

3. The method according to claim 2, wherein the IP packet scheduling adopts a weighted fair queue scheduling method.

4. The method according to claim 1, wherein the IP packet scheduling employs a random early detection technique to prevent queue congestion.

5. The method according to claim 1, further comprising the step of: media access control of a common transmission channel or a shared channel in a downlink direction

(MAC) layer packet scheduling, using the DSCP value of the core network tag from the Iu-PS to determine the priority of each logical channel;

Applying the determined priority of each logical channel to a transmission format combination set selection method; and

Output MAC layer packet scheduling.

6. The method according to claim 5, wherein the priority of each amusement channel is further determined in combination with radio resource related information.

7. The method according to claim 5 or 6, wherein the priority of each logical channel is determined in combination with the QoS attribute parameters of the RAB provided by the SGSN during the RAB establishment or modification process.

8. The method according to claim 7, wherein the radio resource related information comprises transmit power or downlink interference.

9. The method according to claim 1, further comprising the step of: the RNC classifies the IP packets sent from the lur / Iub interface according to the DSCP value marked from the core network of the Iu-PS;

Mark DSCP values according to predetermined rules;

The output IP differentiates service packets to ensure the downlink service shield (QoS).

10. The method according to claim 9, wherein the slave lur / Iub is combined with the QoS attribute parameters of the RAB provided by the SGSN during the RAB establishment or modification process. The IP packets sent by the interface are classified.

11. The method according to claim 9 or 10, wherein the IP packet sent from the lur / Iub interface is further classified by further combining information related to the current wireless resource.

12. The method according to claim 11, wherein the radio resource related information includes transmit power, downlink perturbation, and the like.