KR20140118659A - Method and apparatus for controlling congestion in wireless communication system - Google Patents

Abstract

The present invention relates to a method and an apparatus for controlling congestion in a wireless communication system. The method for controlling congestion of base stations in a wireless communication system comprises the steps of receiving a message including information on congestion data marking application from a core network node from the wireless communication system; determining whether a packet needs the congestion data marking based on the information on the congestion data marking application when the packet is received from a user′s terminal; and transmitting data packet marked with the congestion information based on the judgement stated above.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a congestion control method and apparatus in a wireless communication system,

The present invention relates to a wireless communication system, and more particularly, to a congestion control method and apparatus in a wireless communication system.

Generally, a wireless communication system has been developed to provide voice service while ensuring user's activity. However, the wireless communication system is gradually expanding not only to voice but also data service, and now it has developed to such a degree that it can provide high-speed data service. However, in a wireless communication system in which a current service is provided, a lack of resources and a higher speed service are required by users, and thus a more advanced wireless communication system is required.

In response to this demand, the standardization of Long Term Evolution (LTE) is underway in the 3rd Generation Partnership Project (3GPP) as one system under development as a next generation wireless communication system. LTE is a technology that implements high-speed packet-based communication with transfer rates of up to 100 Mbps. Various methods are discussed for this purpose. For example, there is a method of reducing the number of nodes located on a communication path by simplifying the structure of a network, and a method of approaching wireless protocols to a wireless channel as much as possible.

The radio access node (RAN) of the radio communication system must transmit and receive data with the user within a limited frequency. If there are more users in the cells of the RAN node, or if the traffic to be sent or received by the user increases, congestion may occur in the RAN, and there is a need for a method for effectively controlling such congestion.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for effectively controlling a congestion state in a wireless communication system.

In order to solve the above problems, a congestion control method of a base station in a wireless communication system of the present invention includes receiving a message including congestion information marking application information from a core network node of the wireless communication system, Determining whether the packet requires congestion state information marking based on the congestion information marking application information, and transmitting the marked data packet with the congestion state information according to the determination.

In addition, in the wireless communication system of the present invention, a congestion related information transmission method of a terminal includes receiving packet filter information from a PDN gateway, determining whether congestion information marking is necessary based on the packet filter when generating a packet to be transmitted, And transmitting congestion information marking application information to the packet to be transmitted, when the congestion information marking is required, to the base station.

A method for congestion control of a base station in a wireless communication system of the present invention includes receiving a packet including congestion information marking application information from a terminal, extracting a header from the packet to determine whether congestion information marking is required, And transmitting the marked packet with the congestion information if the congestion information marking is required and the base station is in a congested state.

In addition, in the wireless communication system of the present invention, the base station controlling congestion includes a wired / wireless communication unit for performing communication with the terminal or the core network nodes, and a message including congestion information marking application information from the core network node of the wireless communication system A control unit for determining whether or not the congestion state information marking is required for the packet based on the congestion information marking application information upon receiving a packet from the user terminal and controlling the congestion state information to transmit the marked data packet according to the determination .

In addition, in the wireless communication system of the present invention, a terminal for transmitting congestion related information includes a transmitter / receiver for transmitting / receiving signals to / from a base station, and a receiver for receiving packet filter information from a PDN gateway, If the congestion information marking is necessary, the control unit controls the congestion information marking application information to be transmitted to the base station by including the congestion information marking application information in the packet to be transmitted.

The base station controlling congestion in the wireless communication system of the present invention includes a wired / wireless communication unit for communicating with a terminal or core network nodes, and a packet including congestion information marking application information from the terminal and extracting a header from the packet And a controller for determining whether or not the congestion information marking is necessary and controlling the congestion information marking and transmitting the marked packet if the BS is in a congested state.

According to the present invention, a congestion state can be effectively controlled in a wireless communication system.

1 is a diagram illustrating a structure of an LTE mobile communication system according to an embodiment of the present invention.
Figure 2 illustrates a method for delivering congestion information using a user plane in accordance with an embodiment of the present invention.
FIG. 3 illustrates a method for indicating to a RAN node whether to apply congestion information marking in a congestion event according to an embodiment of the present invention. FIG.
FIG. 4 is a flowchart illustrating a method of transmitting a necessity of marking of congestion information to a RAN node when a UE switched to an idle mode is switched to a connected mode according to an embodiment of the present invention. .
FIG. 5 illustrates an operation for determining whether to apply congestion information marking through a packet filter for each IP flow according to an embodiment of the present invention. FIG.
6 is a flowchart showing the operation sequence of the user terminal shown in FIG. 5;
FIG. 7 is a flowchart showing the operation sequence of the RAN node, that is, the base station shown in FIG. 5;
Figure 8 is a flow diagram illustrating a process for configuring a RAN node to apply congestion information marking only to a particular IP flow, in accordance with another embodiment of the present invention.
9 is a diagram illustrating an internal structure and an internal operation of a user terminal according to another embodiment of the present invention.
10 is a diagram illustrating a concept of a user terminal and a communication system according to another embodiment of the present invention.
11 is a diagram illustrating an operation for allowing a user terminal to find and connect to an SCF according to another embodiment of the present invention.
FIG. 12 is a flowchart illustrating a process in which a SCF performs setting of a user status information report to a user terminal according to another embodiment of the present invention. FIG.
13 is a flowchart illustrating a method for an SCF to find an MME connected to a user terminal in accordance with another embodiment of the present invention.
14 is a flow chart illustrating a process for another embodiment in which the SCF looks for an MME for a user terminal;
15 is a flowchart showing a process of marking and sending congestion information to a user plane and a method of using information of a UE state analyzer at the same time according to another embodiment of the present invention;
Figure 16 shows an embodiment in which the congested state of the RAN is conveyed through the control plane;
17 illustrates an embodiment in which a RAN node controls a user terminal based on status information of a user terminal and congestion information of the network.
FIGS. 18 and 19 are diagrams for explaining an operation of a RAN node controlling a user terminal based on state information of a terminal and congestion information of a network according to another embodiment of the present invention.
20 is a diagram illustrating a method of utilizing an SCF and an ANDSF according to another embodiment of the present invention;
21 is a block diagram illustrating an internal structure of a user terminal according to an embodiment of the present invention;
22 is a block diagram illustrating an internal structure of a RAN node, i.e., a base station according to an embodiment of the present invention;
23 shows a congestion control operation according to an embodiment of the present invention;
24 is a flowchart showing a congestion control operation according to another embodiment of the present invention;
FIG. 25 is a flowchart showing a process of non-priority scheduling according to an SCI range value set in a terminal when a base station is in a congestion state; FIG.
26 is a flowchart showing an operation procedure according to another embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Further, in describing embodiments of the present invention in detail, while the basic 3GPP (Third Generation Partnership Project) LTE system will be the main object, embodiments of the present invention may be applied to other communication / computer systems It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. For example, the present technology for an LTE system can be applied to a UTRAN / GERAN system having a similar system structure. In this case, the ENB (RAN node) may be replaced with the RNC / BSC, the S-GW may be omitted or included in the SGSN, and the P-GW may correspond to the GGSN. Also, the bearer concept of the LTE system can correspond to the PDP context of the UTRAN / GERAN system.

According to an embodiment of the present invention, congestion information is exchanged using user plane data (User Plane Data) instead of control plane signaling in order to reduce the system load due to the congestion information exchange. Herein, the user plane data includes user data packets to be actually exchanged with PDN (Packet Data Network) and header information for transmitting them.

1 is a diagram illustrating a structure of an LTE mobile communication system according to an embodiment of the present invention.

1, a radio access network of an LTE mobile communication system includes an Evolved Node B (EUTRAN) 130, a Mobility Management Entity (MME) 150, And an S-GW (Serving-Gateway) 140.

A user equipment (UE) 100 accesses an external network through an ENB 130, an S-GW 140, and a P-GW (PDN-Gateway) 160.

The AF (Application Function) 110 is a device that exchanges information related to an application at the level of a user and an application.

The PCRF 120 is a device for controlling a policy related to a user's QoS, and a PCC (Policy and Charging Control) rule corresponding to the policy is transmitted to the P-GW 160 and applied.

The ENB 130 is a Radio Access Network (RAN) node, and corresponds to the RNC of the UTRAN system and the BSC of the GERAN system. The ENB 130 is connected to the UE 100 through a radio channel and performs a similar role as the existing RNC / BSC.

In LTE, since all user traffic including a real-time service such as Voice over IP (VoIP) through an Internet protocol is serviced through a shared channel, a device for collecting and scheduling situation information of UEs 100 is required The ENB 130 is responsible for this.

The S-GW 140 is a device for providing a data bearer, and generates or removes a data bearer under the control of the MME 150.

The MME 150 is a device responsible for various control functions, and one MME can be connected to a plurality of base stations.

The Policy Charging and Rules Function (PCRF) 120 is an entity for collectively controlling QoS and accounting for traffic.

The radio access network (RAN) must transmit data to and receive data from the user within a limited frequency range. Congestion may occur in the RAN if the number of users in the cell of the RAN node is increased or the traffic of the user is increased. Congestion control considering user characteristic or service application is needed to cope with congestion situation without deteriorating user experience service quality in such RAN congestion situation (hereinafter, used in the same manner as User Plane congestion situation).

A system component that can perform operations corresponding to such a congestion state can be a user terminal, a communication network, and a server for transmitting traffic.

If congestion occurs in the RAN and congestion control system component is not a RAN node, the congestion information of the RAN (eg, congestion or severity of congestion) should be delivered to the congestion control element . However, the congestion state of the RAN may change with time, and if the congestion state changes in a plurality of RAN nodes, the information exchange is frequently performed according to the change of the congestion state of the RAN, thereby increasing the load of the system.

On the other hand, when congestion control is applied in a network congestion situation, it is possible to determine the transmission order and the order of data packets through the priority in consideration of both the state of the communication system and the state of the user. During this process, consideration should be given to the status of the user, ie, which service application (application or service) the user is using, whether traffic containing information that the user should immediately acknowledge, and the like.

SUMMARY OF THE INVENTION The present invention addresses such a problem and proposes an effective congestion control method.

2 is a diagram illustrating a method for delivering congestion information using a user plane according to an embodiment of the present invention.

The RAN node 210, which is a congestion state, receives a user data packet (transmitted between the UE and the RAN node through the PDCP layer) from the UE 1200 as in step S210, You can use the branch method.

The first method (Option A) uses an IP header. That is, upon receiving the PDCP packet, the RAN node 210 extracts the nested IP packet and transmits it to the PGW via the GW 220 (SGW or SGW). Include information (congestion, congestion, etc.). If it is necessary to transmit only the congestion information, ECN marking can be simply applied to the IP header.

If the degree of congestion (relative severity of congestion, maximum supportable transmission rate, etc.) needs to be conveyed, it may include an extension header including the degree of congestion. When the IP packet including the congestion information arrives at a node in the transmission path, it can be determined whether to include the same congestion information in the IP header when the IP packet is transmitted to the next hop.

In step S230, the UE 100 may transmit the IP packet containing the congestion related information to the AF 2130. [

Another way is to use the GTP-U header. That is, when a packet is transmitted in a network, an IP packet is transmitted through a GTP-U tunnel, and a GTP-U header is added to the IP packet for tunneling. That is, when the RAN node 210 transmits a data packet to the SGW 220, the RAN node 210 attaches a GTP-U header to the RAN node 210, which is the same in the communication between the SGW and the PGW.

When congestion occurs, the RAN node 210 may include congestion information (such as congestion or congestion) in the GTP-U header as in step S240, and forward it to the next node through steps S250 and S260 .

At this time, the congestion information included in the GTP-U is used in the service class indicator (SCI) field (filed) of the GTP-U header or in a separate congestion notification extension header Lt; / RTI >

In case of using the SCI, the nodes (RAN node and SGW / PGW) sending and receiving the GTP-U packet can inform or determine the congestion state according to the SCI value according to predetermined information and / or set information.

For example, SCI 0 can be used to indicate no congestion, and 1 can be used to indicate that congestion exists. Alternatively, SCI # 3 may be used to request congestion to limit the data rate to 50 kbps. That is, the SCI can be used in combination with an identifier for notifying the status of congestion and control requests and parameters for a specific user / service.

Meanwhile, the RAN node may generate a dummy packet (which does not need an actual payload) if the uplink packet does not occur for a long period despite the congestion, and may transmit the GTP-U header including the information to the S-GW . In this case, information indicating that the currently transmitted GTP-U packet is a dummy packet may be included.

The receiving node interprets the meaning of the SCI value to perform congestion control, that is, determination of transmission / order, change of a traffic transmission parameter, or transmission of congestion information to another node.

In this embodiment, conveying congestion information using the user plane is based on marking up congestion information in the IP header or GTP-U header at the node. In general, the RAN node 210 determines whether the user terminal Often, they do not have information related to the application. In this case, the RAN node can simply apply the congestion information marking to all generated packets or randomly extracted packets.

The problem with this method, which can be used without any specific criteria, is the problem of increasing the processing load and increasing the header size of the RAN node. Another problem is that if the congestion information is delivered to the AF (Application Function, generally a server in the PDN) 230, indiscriminately generated congestion information is delivered to the AF where congestion control is not negotiated properly It is possible. In this case, the congestion control may be performed in an unintended manner. For example, a 3GPP operator may expect to lower the transmission rate only based on congestion information, but the situation may arise such that AF blocks the service itself.

A similar situation can arise if the user terminal is roaming or receiving service from a network sharing RAN. In other words, the RAN node to which the user is connected has a function of transmitting congestion information by attaching the congestion information to the packet. The core network node (for example, PGW) may not support this function or may not apply it to the support. In this case, the core network node may ignore the congestion information contained in the user data packet (GTP-U header or IP header). However, in this case, unnecessary increase in packet size or load of packet processing of the RAN node can not be avoided. Alternatively, if the user terminal is roaming and the PDN connection is set to Home Routed, the RAN node belongs to VPLMN (Visted PLMN, roaming service provider), and P-GW belongs to HPLMN (Home PLMN, It belongs. At this time, the VPLMN should be able to not expose its congestion state to the HPLMN.

In order to solve the above situation, the present invention proposes a method for determining whether congestion information is required for each EPS bearer or access point name (APN) or PDN connection.

Conceptually, the core network is configured to determine whether congestion information delivery can occur for packets belonging to the PDN connection or EPS bearer when creating a PDN connection based on subscription information or service application information, or when generating an EPS bearer do. Based on this, the RAN node determines whether congestion information marking is applied when congestion occurs.

3 is a diagram illustrating a method for indicating whether to apply congestion information marking to a RAN node in the event of congestion according to an embodiment of the present invention.

As shown in FIG. 3, the core network node, for example, PCRF 340 determines whether congestion information marking (i.e., congestion information marking application information) is required when an EPS bearer (or PDN connection) To the RAN node 310 through the control plane message. For example, as shown in FIG. 3, the PCRF 340 transmits an IP CAN modification message including a CN required IE field to the GW 330, 330 transmits a bearer creation request message (Create Bearer Request) including the CN required IE field to the MME 320 in step S320. In step S330, the MME 320 transmits a Bearer Setup Request message or an Initial Context Setup Request message including an information marking application field (CN required IE) to the RAN node 310, Lt; / RTI >

Information on whether or not the congestion information marking is applied is set by the PGW 330 based on the information received from the PCRF 340 and then transmitted to the RAN node 310 through the SGW 330 and the MME 320 Or may inform the RAN node 310 that the MME 320 has set up according to the subscription information or the QoS setting.

The RAN node 310 having received the bearer setup request message stores it in step S340, and determines in step S360 whether to mark the congestion state information when a packet belonging to the EPS bearer arrives in step S350. Alternatively, the RAN node may determine whether to send congestion status information for that EPS bearer when a congestion status report is needed.

Meanwhile, in the above embodiment, if the unit of control for congestion information marking is a PDN connection, the necessity of congestion information marking (congestion information marking application information) is set in the step of setting a default bearer, 310) (i.e., the Create Bearer Request message is replaced with the Create Session Request message in operation S320). And then the RAN node 310 may apply the congestion information marking applied to the default bearer to all bearers belonging to that PDN connection.

Meanwhile, if the control unit for the congestion information marking is the EPS bearer, the core network node can set whether to mark the congestion information when each EPS bearer is set and / or modified. The congestion information marking of the RAN node depends on the setting of each EPS bearer.

On the other hand, during this process, the MME can remember whether congestion information marking is required for each bearer or PDN connection. In addition, the MME can determine whether to use the congestion information reporting function using the user packet for each core network node (e.g., PGW) during the above process, and store the result. If a PDN connection or bearer is created for a user terminal that uses the same core network node (eg, PGW), then the MME may apply the same settings, even if it does not receive explicit congestion information from the core network node, The RAN node can be informed of the use of congestion information. In this case, an S1 bearer setup request message (or S1 initial context setup request message) may be used as in the above embodiment.

FIG. 4 is a flowchart illustrating a method of transmitting a necessity of marking of congestion information to a RAN node when a UE switched to an idle mode is switched to a connected mode according to an embodiment of the present invention. to be.

4, in order to switch from the idle mode to the connected mode, the UE 400 transmits an RRC connection completion message (hereinafter referred to as an RRC connection completion message) including a service request RRC connection complete) to the RAN node 410, and the RAN node 410 transmits an initial UE message including the service request to the MME 420.

When a core network node (e.g., MME) 420 receives a service request from the UE 400 and sets a bearer context to the RAN node 410, the core network node The initial context setup request message may be set to indicate whether or not the congestion information marking is required as the bearer information and transmit the initial context setup request message. More specifically, the initial context setup request message includes E -RAB to be setup item Can be implemented by adding one field (eg CN required) to IEs indicating whether congestion information marking is required.

Then, in step S440, the RAN node 410 stores information on whether or not the congestion information marking is necessary. Thereafter, when the RAN node 410 receives the PDCP packet from the UE 400, it determines whether it is necessary to mark the congestion information in step S460, and consequently, the data packet marked with the congestion information, Node. Alternatively, the RAN node may determine whether to send congestion status information for that EPS bearer when a congestion status report is needed.

In the above embodiments, an identifier (e.g., CN required IE) indicating whether the core network node requires congestion information is an identifier indicating whether the generated PDN connection or EPS bearer is home routed or local breakout Routed Indicator). If the user terminal is in a roaming situation, the RAN node or the core network node (eg, S-GW) receiving the information indicating that the PDN connection or the EPS bearer is home routed may implicitly know not to transmit the congestion information .

Although the method according to the embodiment can prevent the congestion information marking from being applied indiscriminately at the RAN node, there is a limit that the minimum division unit is the EPS bearer.

If a plurality of IP flows are being transmitted to one EPS bearer and only a specific IP flow needs to exchange congestion information, the method according to the embodiment may not be preferable.

In order to solve such a problem, in another embodiment of the present invention, when generating an EPS bearer (or PDN connection), whether or not the core network needs to mark congestion information for each packet filter included in a TFT (Traffic Flow Template) When the user terminal notifies the user terminal of the congestion information and notifies the RAN node whether the packet filter matches the congestion information when the packet is generated, the RAN node notifies the corresponding packet whether the congestion information is marked We suggest a way to make judgment.

If there is an indicator that congestion information marking is allowed in the header of the packet received from the user terminal, the RAN node can mark congestion information in the GTP-U or IP header.

This is because the user terminal can distinguish IP flows within the EPS bearer through packet filters received from the core network.

In summary, it is possible to determine whether congestion information marking is applied through the packet filter for each IP flow.

FIG. 5 is a diagram illustrating an operation for determining whether to apply congestion information marking through a packet filter for each IP flow according to an exemplary embodiment of the present invention. Referring to FIG.

As shown in FIG. 5, the PCRF 540 may transmit information to the PGW 530, including the SDF template information and information on whether to apply congestion information marking to the IP CAN session modification message. The PGW 530 then transmits a set of packet filters or a TFT (Traffic Flow Template) message to a bearer create (update) bearer request message for bearer creation (modification) In this case, information indicating application of congestion information marking to IP flows matched to the corresponding filter may be added to each packet filter.

In step S530, the MME 520 receives the ESM (EPS) message, for example, an Activate Dedicated Bearer Request (ESM) message sent to the UE 500, packet filter) or TFT and congestion information marking necessity information together.

In step S540, the user terminal 500 stores information on whether to apply the packet filter and the congestion information marking. If a packet of the IP flows is generated, the user terminal 500 transmits a packet filter for bearer mapping, Confirm whether congestion information marking is required when using

If congestion information marking is required for the matching packet filter, the user terminal 500 may add a header or control field to attach the packet to the RAN node 510 as in step S550, The MAC PDU includes a PDCP header or a MAC CE (Control Element) including whether congestion information marking is required or not. In addition, the user terminal may transmit information indicating whether the corresponding packet is attended or unattended traffic in the PDCP header or MAC CE.

In step S560, the RAN node 510 receives and transmits the congestion information to the GTP-U or the IP header only for packets for which congestion information marking is required.

On the other hand, when the RAN node 510 receives a PDCP packet including information indicating that congestion information marking is necessary, it is not necessary to indicate that congestion information marking is required for the explicitly received PDCP for packets belonging to the same IP flow , Congestion information marking may be applied. If the packet received from the user terminal includes attended or unattended, the RAN node may consider this in the resource allocation or scheduling step.

6 is a flowchart showing the operation procedure of the user terminal shown in FIG.

As shown in step S610, the user terminal receives information on the packet filter and whether or not the congestion information marking for each filter is applied from the PGW in step S610.

If the user terminal detects that an IP packet is generated in step S620, the user terminal proceeds to step S630 and performs packet filtering and bearer mapping. Then, the user terminal proceeds to step S640 and confirms whether the congestion information marking is required for the IP packet.

If necessary, the user terminal proceeds to step S650, marks the congestion information in the PDCP header, and transmits the PDCP packet to the RAN node in step S660. The PDCP header is an embodiment of the present invention, and the user terminal may include the information in any kind of header or message sent to the RAN node.

7 is a flowchart showing the operation sequence of the RAN node shown in FIG. 5, that is, the base station.

As shown in step S710, the base station receives the PDCP packet from the user terminal UE. In step S720, the BS extracts the PDCP header.

In step S730, the BS determines whether congestion information marking is required for the packet and whether the current BS is in a congested state.

If congestion information marking is required and the base station is in a congested state, the base station proceeds to step S740 and writes the congestion state in the IP header or GTP-U header.

Thereafter, the BS proceeds to step S750 and transmits the PDCP packet to a next node, for example, a SGW or the like.

On the other hand, the operation of setting the RAN node to apply the congestion information marking only to a specific IP flow may be performed using a method of notifying by using the GTP-U header in the GW node, and a method for this is shown in FIG.

FIG. 8 is a flowchart illustrating a process of configuring a RAN node to apply congestion information marking only to a specific IP flow, according to another embodiment of the present invention.

If the congestion information is required for a specific IP flow, the PGW 820 transmits an indicator indicating that congestion information marking is necessary to the forwarding packet in the header of the GTP-U packet transmitted toward the RAN node 810 through step S820 an indicator can be added.

The information may be delivered by inserting a separate extension header to indicate congestion notification required_ in the GTP-U header, or by sending an SCI (810) between the RAN node 810 and the GW 820 Lt; / RTI >

For example, if the SCI value is 1, the bearer of the corresponding GTP-U packet or the uplink packets belonging to the IP flow are transmitted to the RAN node 810 Congestion information marking is applied and can be operated in a way that does not apply when the SCI value is zero.

In this manner, if the PGW 820 is configured to apply congestion information marking to the RAN node 810 for a particular IP flow, then the RAN node 810 stores information about it (not shown) .

If the PDCP packet is received from the user terminal 800 in step S830, the RAN node 810 determines whether congestion has occurred and whether congestion information is allowed to be written in step S840. And writes it in the congestion notification field.

In step S850, the RAN 810 transmits the data packet to the next node, for example, SGW.

Meanwhile, the core network node can inform the RAN node of whether to use the congestion information report using the user data packet by using a separate GTP message. In other words, if the congestion information is not needed and the RAN node transmits the data packet including the congestion information, the core network node informs the GTP message so that the RAN node can no longer include the congestion information.

The message used at this time is one of the GTP-C Path Management Message (GTP-C Path Management Message), and may be, for example, a Congestion Notification Required Message.

Conversely, if congestion information is needed and congestion information does not arrive, the core network node may inform the RAN node to include the congestion information in the data packet via the GTP message. The message used at this time may be a GTP-C path management message (GTP-C Path Management Message_, for example, a Congestion Notification Not Required Message). If the PGW transmits the GTP message In this case, the SGW interprets it, applies it to the message sent to the PGW (it can add or subtract congestion information depending on whether congestion information is included or not), and transmits a message informing the request of the PGW to the corresponding RAN node.

Whether or not the congestion status of the RAN is transferred to other core network nodes may be determined according to the service provider to which the user is subscribed and the service provider that is currently providing the service. A home network entity (e.g., a RAN node or an S-GW) of a service provider providing access network service to a user terminal (referred to as Serving PLMN and corresponding to a Visited PLMN in the case of a roaming situation) It may not transmit the RAN congestion state information to another core network entity (e.g., P-GW) for the user terminal. At this time, the HPLMN ID of the user terminal and the ID of the Serving PLMN to which the network entity belongs can be compared. Alternatively, the network entity of the Serving PLMN can determine whether the congestion information is delivered by comparing the HPLMN ID of the user terminal with the list of PLMNs that allow or disallow congestion information set in the UE. The HPLMN ID of the user terminal may be included in a part of the IMSI. The transmission / non-transmission of congestion information per PLMN can be set in the network entity by the O & M method. If congestion information should not be conveyed, the core network entity (eg, S-GW) may not forward the congestion information received from the RAN to another core network entity (eg, P-GW) have. Or congestion information is included in the packet header, the core network entity (eg, S-GW) may delete it from the header information and then forward the packet to another core network entity (eg, P-GW). This may be to avoid exposing the congestion situation to the PLMN that owns the P-GW, or to avoid the overhead of providing information that will not be used, by the PLMN that owns the RAN.

In addition, the core network entity (e.g., S-GW) can apply congestion control itself according to the congestion state received from the RAN and the HPLMN of the user terminal. For example, the congestion control policy for each PLMN is set in the S-GW by a method such as O & M, and the S-GW receiving the congestion state information from the RAN node transmits congestion information to the P-GW according to the embodiment However, it is possible to apply congestion control by searching the congestion control policy for each PLMN corresponding to the HPLMN of the user terminal. More specifically, one or more of the following congestion control policies may be set in the S-GW.

<PLMN, RAN congestion state, Traffic shaping rule>

The PLMN corresponds to the PLMN ID, and the RAN congestion state simply indicates whether the RAN is congested or the congestion degree of the RAN (for example, low, medium, high, etc.) The congestion control policy to be applied to the traffic of the terminal, for example, dropping the packet, adjusting the transmission rate to X bps, or the like.

Further, the above embodiments may be applied to a case where the PDN connection or the type of the EPS bearer is Home Routed according to the above-described embodiment instead of comparing the PLMN IDs.

On the other hand, the core network node may inform the RAN node whether to report the congestion state using the user data packet header by using some of the QoS parameters. For example, the RAN node and the core network node use QCI and ARP (Allocation and Retention Priority) as QoS parameters for the EPS bearer. If these QoS parameters have a specific value or belong to a specific value range, The node determines that it is necessary to inform the congestion state using the user data packet.

More specifically, for example, when a core network node (e.g., a PGW) wants to receive a congestion status of a RAN through a header (GTP-U header or IP header) of a user data packet, QCI) to a specific value, or to set the ARP (or QCI) to fall within a specific range. The RAN node having the QoS parameter (for example, ARP / QCI value or range indicating that congestion information is required) is set to the ARP / QCI value or the ARP / , It is possible to know whether or not to send the congestion information to the packet sent to the core network node. If it is determined that congestion information is needed, congestion information may be included in the packet sent to the core network.

Meanwhile, according to another embodiment of the present invention, a core network node (e.g., PCEF or TDF) receiving congestion information of the RAN can perform congestion mitigation. At this time, the core network node can determine how to handle the traffic according to the congestion state.

The PCRF, which provides rules (eg, PCC rule or ADC rule) to the core network node (eg PCEF or TDF), generates a rule for setting the policy for the operation of the core network node according to the congestion condition, To the network node. When the PCRF determines the operation rule according to the congestion state condition to be used in the core network, the subscription information of the user such as the membership level and the type of the service and / or the application may be considered.

23 is a diagram showing a congestion control operation according to an embodiment of the present invention.

The PCRF 2320 generates a rule to be transmitted to the core network node, as shown in step S2330. At this time, the PCRF 2320 may consider the generation of the congestion status when the congestion status such as the congestion level is received in step S2320. In addition, the PCRF 2320 may consider the generation of a rule when there is a subscription data of the user such as the membership level received from the SPR 2330 or the HSS through step S2310.

The congestion state based rules generated by the PCRF 2320 may include information capable of detecting a data flow and policy control information to be applied to a data flow have. The policy control information may describe a processing operation of a data flow according to a congestion state condition.

The policy control may include a gate status indicating whether a data flow is transmitted or not and a maximum / guaranteed bitrate applied to the data flow. Information can be extended to a form that is applied as a congestion condition. If the congestion state condition is included in the policy control, the core network entity applies the corresponding policy (gate status application or bitrate application) only when the congestion state condition is satisfied.

<Policy control>

{Priority 1, load level> X, gate status = open, DL-maximum bitrate = 50kbps, UL-maximum bitrate = 50kbps}

{Priority 2, load level Y, gate status = open, DL-maximum bitrate = 30kbps, UL-maximum bitrate = 30kbps}

{Priority 3, load level Z, gate status = closed, DL-maximum bitrate = 30kbps, UL-maximum bitrate = 30kbps}

For example, PCRF uses policy control to limit the maximum bitrate of the data flow to 50 kbps when the congestion level is X or more, and when the congestion level is greater than Z, It is also possible to set the gate status of the data flow to be closed.

That is, the PCRF can set the rules for the core network entity (eg PCEF or TDF) to perform some action when the congestion state is at a certain level. These rules may be made based on the subscription information of the user terminal or the characteristics of the service and / or application. For example, rules can be set so that the bitrate is not limited even when congestion occurs in a case where the user's subscription level is high (e.g., gold membership), and when the subscription level is low, Even in a situation, a rule can be set to limit the bitrate. Operations and / or settings according to congestion state conditions may have a relative priority. Such a configuration is an example for explaining the concept of the present invention, and the major concept and operation of the present invention can be applied to a similar structure without much change even if it is limited to the structure of specific fields of the rule.

Meanwhile, in order for the RAN node to know the service or application to which the user data belongs, the core network entity (for example, P-GW or TDF) transmits the GTP-U header of the data packet to the RAN node . In order to detect the service or application characteristics of a user data packet, the core network entity must probe the packet (Deep Packet Insepction), which is the work done using the resources of the core network entity. Therefore, it is desirable that the service characteristic detection and marking performed in the core network node is variably applied according to the congestion state.

For example, a core network node may perform effective scheduling in a RAN node by performing service characteristic detection and marking on a packet transmitted through a congested RAN, and may detect a service characteristic for a packet transmitted through a non-congested RAN It is possible to reduce unnecessary load.

The PCRF 2320 may generate a rule for setting the operation of the core network entity (e.g., P-GW or TDF) (for example, the PCC rule or the ADC rule) and provide the generated rule through the step S2340. That is, the PCRF can create and provide rules for controlling the service characteristic detection and marking according to the RAN congestion state in the core network entity. At this time, the subscription information of the user terminal such as the subscription level can be considered together.

The core network entity which received the PCC rule or the ADC rule from the PCRF 2320 can control the congestion according to the provided rule through step S2350.

FIG. 24 is a flowchart showing a congestion control operation according to another embodiment of the present invention.

The PCRF 2420 generates a rule (ACC or ADC rule) to be transmitted to the core network node in step S2430. At this time, the PCRF 2420 may consider this if the congestion status such as congestion level is received in advance in step S2420. Alternatively, the PCRF 2420 may consider the SPR 2430) or the subscription data of the user, such as the membership level received from the HSS in step S2410, may be considered.

The congestion state-based rule generated by the PCRF 2420 may describe the service property detection and marking operation of the data flow according to the congestion state condition. That is, the rule may include whether service characteristic detection and marking is required depending on the congestion state condition. If the congestion state condition is included in the rule, the core network entity can perform the service characteristic detection and marking operation only when the congestion state condition is satisfied.

{Priority 1, load level < X, service detection and marking = no}

{Priority 2, load level < Y, service detection and marking = yes}

For example, if the congestion level is X or less, the PCRF 2420 can be configured not to perform the operation of detecting the service characteristic in the core network entity and inserting it into the GTP-U header. The PCRF 2420 can also be configured to perform the operation of detecting the service characteristic in the core network entity and inserting it into the GTP-U header if the congestion level is Y or more.

That is, the PCRF 2420 may set the rules for the core network entity (e.g. PCEF or TDF) to perform some action when the congestion state is at a certain level. These rules may be made based on the subscription information of the user terminal or the characteristics of the service and / or application. For example, if the user's subscription level is high (eg, gold membership), service characteristics detection and marking may be performed even in a situation where congestion is not very high, so that the RAN node may apply an improved scheduling method considering service characteristics Can be done. Operations and / or settings according to congestion state conditions may have a relative priority.

The PCRF 2420 may generate a rule for setting the operation of the core network entity (e.g., P-GW or TDF) (e.g., the PCC rule or ADC rule described above) and provide the generated rule through S2440. The core network entity 2410 may then initiate and / or stop the traffic detection according to the congestion level, via step S2450.

In step S2460, the core network entity 2410 detects service characteristics according to the provided rule and performs or does not perform a marking operation.

The above-described configuration is an example for explaining the concept of the present invention, and the major concept and operation of the present invention can be applied to a similar structure that is limited to the structure of specific fields of the rule without much change. In the same communication system, data is transmitted and received through a bearer. When data is transmitted / received through a bearer, a control message for controlling the IP flow is transmitted / received between network entities There is an advantage that it is not necessary.

However, when congestion occurs in the base station, it is difficult to differentiate a plurality of IP flows (IP flows) transmitted through a single bearer in a differential manner. In order to overcome this problem, a traffic detection function existing behind the P-GW or a deep packet inspection in the PGW is performed to distinguish services of IP flows, Marking a service class indicator (SCI) in the GTP-U header so that the SCI marking is passed to the base station via the SGW, thereby allowing the base station to adjust the scheduling as needed.

However, there is a problem that SCI marking and scheduling according to the SCI are commonly applied to all terminals.

According to another embodiment of the present invention, in order to use a new service, control messages are not exchanged every time an IP flow occurs, and at the same time, SCI marking is performed at a subscription level level), we propose a mechanism that can be applied differently for each terminal.

In the embodiment of the present invention, the IP flows that are de-prioritized are defined as unattended, and the SCI range value that distinguishes between unattended and attended according to the subscription level of the terminal is referred to as &quot; connected mode, it transmits the context of the terminal to the base station.

The base station receiving the context of the UE including the SCI range value that distinguishes between unattended and attended can use this to detect packets that are classified as unattended to be de-prioritized when the base station is in a congestion state And stores them in a queue different from the packets classified as attended in the same bearer, and de-prioritizes the scheduling of packets in the unattended queue to differentiate the packets.

The detailed execution process is shown in Fig.

FIG. 25 is a flowchart showing a process of non-priority scheduling according to the SCI range value set in the UE when the BS is in a congestion state.

The terminal 2510 transmits an attach request / service request / tracking area update message including an active flag to the MME 2530 through the base station 2520 to transmit the data And requests switching to a connected mode for transmission and reception.

If the MME 2530 having received the message has received an attach request or has received a tracking area update request with the context of the terminal not in the MME 2530 It transmits a location update request to the HSS 2560 in step S2510 and receives a location update response including the subscription data of the terminal in step S2515. At this time, the subscription data may include information about the subscription level (e.g., high, medium, low) of the corresponding terminal.

The MME 2530 transmits the SCI to be classified as unattended in consideration of the contract relationship with the home operator of the roaming user and the received subscription level when the terminal is a roaming user in step S2520, Determine the QCI range. The determined SCI / QCI range for the UE is as shown in step S2525. Is included in an initial UE context setup request message for setting context information of the UE to the BS and is transmitted to the BS 2520.

When the MME 2530 transmits an initial UE context setup request message, the MME 2530 delivers an attach accept message to be transmitted to the UE 2510 to the base station 2520, The base station 2520 delivers the connection acceptance message to the terminal 2510 in step S2530.

The base station 2520 receiving the SCI / QCI range value included in unattended determined from the MME 2530 for the terminal 2510 stores it in the context of the terminal in step S2535. The base station 2520 transmits an initial UE context setup response message to the MME 2530 in step 2540. The MME 2530 receives the response from the base station 2520 in step 2540, The base station 2530 transmits a data base plane data plane information to the SGW 2540 at step S2545 / S2550 to form a data plane connected to the base station and the SGW / session request) or a modify bearer request. The SGW 2540 sends the same message as the message to the PGW 2550.

The PGW 2550 transmits a create session response or a modify bearer response to the SGW 2540 in step S2555 / S2560. The SGW 240 then transmits the same message to the MME 2530 so that the data plane for the UE 2510 is connected to the SGW 2540 / PGW 2550 from the base station.

 After the establishment of the data plane for the terminal 2510, when data arrives from the outside, the data is analyzed in the PGW / TDF 2550 through the step 2565, IP flow, the SCI is marked in the GTP-U header. Then, the PGW 2550 delivers the IP packet marked in step 2570 to the SGW 2540.

Then, in step 2575, the SGW 2540 marks the received SCI marking in the GTP-U header that is directly transmitted to the base station, and transmits the marked data to the base station 2520.

Upon receiving the data including the SCI marking, the base station 2520 confirms the congestion state of the data plane (S2580), and if it is congested, the base station 2520 transmits the terminal context of the terminal The BS 2520 confirms whether the received SCI is classified as unattended and if it is classified as unattended, the BS 2520 generates and manages queues for managing other packets of the same bearer, And de-prioritized among the packets in the bearer rather than unattended packets to be scheduled.

Meanwhile, in another embodiment, the IP flows that are de-prioritized are defined as unattended and the SCI range value that distinguishes unattended and attended according to the subscription level of the terminal is set as the SCI marking to the PGW for marking. Then, since the SCI marking is started in the PGW only when unattended traffic occurs, the load for marking the PGW can be reduced. Also, when a data packet including SCI marked by PGW arrives at the base station, it distinguishes traffic that should be distinguished as unattended according to the degree of congestion of the base station by presence or absence of SCI, de-prioritization processing to perform differential processing.

26 is a flowchart showing an operation procedure according to another embodiment of the present invention.

The terminal 2600 transmits an attach request / service request / tracking area update message including an active flag to the MME 2620 through the base station 2610 in step S2610, And requests switching to a connected mode for transmission and reception.

When the MME 2620 receiving the message receives an attach request or receives a tracking area update request in a state where the context of the UE is not in the MME 2620 , And transmits a location update request to the HSS 2650 in step S2615. In step S2620, the MME 2620 receives a location update response including the subscription data of the subscriber station. At this time, the subscription data may include information on the subscription level (e.g., high, medium, low) of the terminal.

In step S2625, the MME 2620 determines whether the terminal is a roaming user by unattended in consideration of the contractual relationship with the home operator of the roaming user and the received subscription level The SCI or QCI range to be classified can be determined.

The MME 2620 transmits information on the range of SCI or QCI to be processed as unattended to the PGW / TDF 2640 through a create session request via the SGW 2630 in step S2630 / S2635 . Also, the MME 2620 may set the range of the determined SCI / QCI to the base station in the process of transmitting the context information of the UE to the base station through an initial context setup request message (not shown in the figure).

The PGW 2640 receiving the information on the range of the SCI or the QCI to be processed as unattended from the MME 2620 stores it and transmits a response to the request of the MME 2620 as a create session response To the MME 2620 in step S2640 / S2645.

In step S2650, when a data packet arrives from outside, the PGW / TDF 2640 performs a deep packet inspection as in step S2655 and determines the SCI for the packet.

If unattended is determined by QCI, it determines the bearer to which the packet will be forwarded and then determines whether the QCI of the bearer corresponds to the range of QCIs to be classified as unattended. If the determined SCI / QCI is not the SCI / QCI range to be considered unattended, the PGW / TDF 2640 does not mark the SCI for that IP flow.

On the other hand, if the determined SCI / QCI is an SCI / QCI range to be considered unattended, the PGW / TDF 2640 inserts the SCI marking into the GTP-U header for the IP flow in step 2660, Data to be transmitted to the base station.

After receiving the data including the SCI marking, the BS 2610 checks the congestion state of the data plane in step 2666, and if it is congested, the BS 2610 of the UE ) To check whether the received SCI is classified as unattended. If the packet is classified as unattended, the BS 2610 generates and processes a queue for managing other packets of the same bearer, thereby processing packets in the same bearer that are not classified as unattended And can be de-prioritized and scheduled.

On the other hand, as mentioned above, when the RAN congestion occurs, it is necessary to consider the state of the user (whether the type of service application being executed or whether the traffic is attended). In addition, changing the operation parameter according to the congestion state (e.g., adjusting the data rate) may also be an effective congestion control method.

However, collecting the state information of the user terminal and adjusting the operation parameters of the service application according to the congestion state are hard to perform in the transmission / reception and control device.

9 is a diagram illustrating an internal structure and an internal operation of a user terminal according to another embodiment of the present invention

As shown in FIG. 9, it is effective to collect / change the status of the user terminal and the parameters of the service application in an operating system (OS) and a terminal status analyzer such as a service application (910) This is because it is difficult to establish an API (Application Programmable Interface) for collecting status information of a user terminal and setting a parameter of a service application in a transmission / reception and control device such as the 3GPP modem of 920.

Accordingly, in another embodiment of the present invention described below, a method of collecting and reporting status information of a user terminal and a method of receiving and setting operation parameters of a service application from a network is proposed.

10 is a diagram illustrating a concept of a user terminal and a communication system according to another embodiment of the present invention.

As shown in the figure, a UE state analyzer (hereinafter, UE state analyzer) 1010 is installed in the user terminal 1000. It may be implemented in SW form or in HW form.

The UE state analyzer 1010 can collect state information of a user terminal through an OS (Operating System), and can change another service application and operation parameters of the user terminal. The UE state analyzer 1010 communicates with a Status / Control Function (SCF) 1020 existing in a provider network. The SCF 1020 may be an AF (Application Function) as long as it exists in the PDN.

The SCF 1020 may set the UE state analyzer 1010 of the user terminal to determine which of the user state information should be reported and the format and period of the report. According to this setting, the UE status analyzer 1010 reports the status of the user terminal to the SCF 1020. Also, the SCF 1020 can set / change operation parameters of the service application being performed by the user terminal and the UE through the UE state analyzer 1010. [

In describing the embodiments of the present invention described below, the user terminal 1000 is a concept including the UE state analyzer 1010.

In order to perform the above operation, the user terminal 1000 should first be able to find the SCF 1020 and try to connect. This discovery operation may be performed by providing the information that the SCF 1020 can be found when the user terminal 1000 is initially registered or attached to the provider network.

11 is a diagram illustrating an operation for allowing a user terminal to find and connect to an SCF according to another embodiment of the present invention.

11, the PGW 1120 delivers the address or ID of the SCF 1130 to the user terminal through the Protocol Configuration Option (PCO) when the PDN connection is created.

That is, the user terminal 1110 inserts a PCO requesting the address or ID (FQDN, etc.) of the SCF into an ESM request message (for example, a PDN connection request message or a session creation request message) And the MME that receives it transmits the PCO to the SGW, and the SGW transmits the PCO to the PGW.

The PGW inserts a PCO containing the address or ID of the SCF when sending a response message (for example, a session creation response message or a PDN connection acceptance message) of the received request message. In step S1120, And transmitted to the terminal.

If the address of the SCF is included in the PCO, the user terminal 1110 can access it using the ID. If the ID is included in the PCO, the user terminal 1110 transmits a DNS or DHCP query as an ID To find the address of the SCF.

The user terminal 1110 having obtained the address of the SCF through the above process can establish an IP session with the SCF in step S1140.

FIG. 12 is a flowchart illustrating a process in which a SCF performs setting of a user status information report and the like to a user terminal according to another embodiment of the present invention.

Referring to FIG. 12, the user terminal 1210 performs a connection process with the SCF 1220 in step S1210.

In step S1220, the SCF 1220 transmits a setup message to the user terminal 1210 to determine what information should be reported and the condition and format and / or period of the report.

The status information that can be reported by the user terminal 1210 includes on / off status and duration of the screen, existence and duration of the user input, on / off (on / off status) of the WLAN, Service application and each IP-5-tuple information.

The reporting condition may indicate a condition under which certain information should be reported, such as a screen off being reported if the screen is off for 5 minutes.

The user terminal 1210 collects the status of the user terminal according to the setting and reports it to the SCF 1220 in step S1230.

The SCF 1220, which has collected the status information from the user terminal 1210, may store the status information of the user terminal in step S1240, change the setting for the report if necessary, or change the operation parameter of the user terminal.

Alternatively, as shown in step S1250, the SCF 1220 may generate information useful for the 3GPP network based on the status information of the user and transmit the information to the PCRF 1230 via the Rx interface.

For example, a service application being executed by the user terminal 1210 and information (IP-5-tuple) capable of grasping their IP flows may be transmitted to the PCRF 1230, It is possible to inform the PCRF 1230 of information such as the state of the user terminal and the traffic that has been attended or unattended in consideration of the type, screen on / off, or presence of input.

The PCRF 1230 receiving this information can perform the process of creating and / or modifying PCC or ADC rules.

If the information collected by the SCF 1220 is to be delivered directly to the MME without going through the PCRF 1230 (i.e., the SCF and the MME can be directly connected), the SCF 1220 sends the information to the user terminal 1210 You should be able to find out what MME is. FIG. 13 shows a method for the SCF to find an MME connected to a user terminal.

FIG. 13 is a flowchart illustrating a method for the SCF to find an MME connected to a user terminal according to another embodiment of the present invention.

Referring now to FIG. 13, the SCF 1320 can locate the MME 1330 associated with the user terminal 1310. The user terminal 1310 may transmit information (MME name, GUTI, or GUMMEI) to the SCF 1320 that can locate the MME 1330 in the step of establishing a connection with the SCF 1320 for the first time in step S1310.

This also includes when the MME 1330 of the user terminal 1310 is changed, the information to find the changed MME is also passed back to the SCF 1320. [

Meanwhile, when the SCF is directly connected to the MME, information that can change the operation of the user terminal may be transmitted in addition to those described in the preceding embodiments.

For example, if the user terminal 1310 transmits remaining battery power or the like to the SCF 1320 as in step S1320, the SCF 1320 may transmit the remaining battery power or the like to the MME 1330 through step 1340, It is possible to transmit the result of the determination that the low power mode is required to the MME 1330 through the UE status information message in step S1340.

Accordingly, the MME 1330 can perform operations such as switching the user terminal to a dormant mode or changing a DRX cycle.

14 is a flow chart illustrating a process for another embodiment in which the SCF searches for an MME for a user terminal.

In another embodiment where the MME for the user terminal shown in FIG. 14 can be found, a method of using the HSS 1440 is described.

The user terminal 1410 performs a security process (authentication and security setting process) when the user terminal 1410 initially connects to the SCF 1420. To this end, the user terminal 1410 transmits a BSF 1420 and a Boost trapping ) Process.

Then, the BSF 1420 may transmit the ID (IMSI or IMPI) of the user terminal 1410 to the SCF 1430 in step S1430 after the authentication process in step S1420.

In step 1440, the SCF 1430 transmits a UE location query message to the HSS 1440 using the ID of the user terminal 1410 to transmit the UE location query message to the MME 1450, which controls the user terminal 1410, Ask for the address of.

The HSS 1440 may then inform the SCF 1450 of the address or ID of the MME 1450 for the user terminal 1410 via the UE location response message in step 1450. [

Since the operation thereafter is the same as that of FIG. 13, detailed description will be omitted.

FIG. 15 is a flowchart illustrating a method of marking and sending congestion information to a user plane and using a UE state analyzer simultaneously according to another embodiment of the present invention. Referring to FIG.

The user terminal 1510 obtains the address of the SCF 1530 in accordance with the previous embodiments in the process of PDN connection and EPS bearer establishment and the network is also connected to the packet filter 1530 for the IP flow towards the SCF 1530 packet filter) may include information that congestion control information marking is required.

Accordingly, the user terminal 1510 can inform the SCF 1530 of the status information of the user terminal, for example, whether the WLAN is on or off, remaining battery level, or the like, through S1510. At this time, information indicating that congestion information marking is necessary may be included in the PDCP header of the packet to be transmitted to the SCF 1530 according to the setting of the packet filter.

The RAN node 1520 may receive the congestion information in the GTP-U header or the IP header for the packet to the SCF 1530 if congestion occurs in step S1520. If congestion information is included in the GTP-U header, the PGW delivers the congestion information to the PCRF, and the PCRF can forward it to the AF again.

The SCF 1530 receiving the congestion information and the status information of the user terminal in step S1530 determines whether it is necessary to change the operation parameters of the user terminal 1510 in step S15410. A command message to change the operation parameters of the user terminal 1510 can be sent to the user terminal. This may include, for example, an instruction to enter a WLAN, a policy to move to a WLAN, and the like.

An operation similar to the above can also be used when the state of the user terminal is delivered to the SCF and the congestion state of the RAN is conveyed through the control plane rather than the user plane, Respectively.

16, when the RAN node 1620 detects that congestion has occurred in step S1610, the RAN node 1620 transmits a Congestion Notification message to the MME, the SGW, the PGW, and the like in step S1620 To the PCRF (1630). In step S1630, the PCRF 1630 transmits an Rx event report message including information on the congestion notification to the SCF 1640. [

Thereafter, the terminal status report is transmitted from the user terminal 1610, and thus the SCF 1640 controls the user terminal 1610 based on the terminal status report, steps S1640 to S1660 are the same as described in the previous description Therefore, detailed description will be omitted.

It is also possible to reset the operation parameters of the service application being executed by the SCF in the user terminal, considering the status information of the user terminal and the congestion information of the network.

17 is a diagram illustrating an embodiment in which a RAN node controls a user terminal based on state information of a user terminal and congestion information of the network.

As shown in FIG. 17, the user terminal 1700 transmits the information of the currently executed service application to the SCF 1710 as in step S1700. And the RAN node 1720 may inform the SCF 1710 of the congestion information at step S1710 via the user plane or the control plane.

Based on this, the SCF 1710 may instruct the user terminal 1700 to change the operation parameters of the service application being executed, and the UE state analyzer 1701 in communication with the SCF 1710 may send a new operation parameter To the service application to be used. An example of the new operation parameter is shown in FIG. 17, which is a wireless LAN (WLAN), and in FIG. 17, the SCF 1710 transmits an operation parameter for turning on the wireless LAN to the user terminal 1700.

18 and 19 are views for explaining an operation of controlling a user terminal by a RAN node based on status information of the UE and congestion information of the network according to another embodiment of the present invention.

In FIG. 18, it is assumed that the user is using a YouTube application.

As shown in FIG. 19, the user terminal communicates information of service applications currently being executed to the SCF 1940 according to the setting.

As in FIG. 16, congestion information may be transmitted together with a message containing such state information in the user plane, or congestion information may be transmitted through the control plane separately. The above steps are shown in steps S1910 to S1930, and the above steps have been described above, so a detailed description will be omitted.

In step S 1940, the SCF 1940 receives the congestion information and determines that the operation parameter of the service application is changed according to the congestion information. For example, if the video streaming service currently requesting 100 kbps is running and congestion information indicates that it can transmit only 50 kbps to the user terminal, the SCF 1940 sends the corresponding It can be instructed to lower the transmission parameter of the service application to 50 kbps or less.

Alternatively, the SCF 1940 may instruct the video service application of the current user terminal to reproduce HD (High Definition) video. If the SCF 1940 is difficult to provide according to the network status, can do.

This operational parameter may be communicated with information that may refer to the target service application, e.g., a service application ID, via a UE configuration message, as shown in step S1950.

The UE state analyzer 1920 receives the target service application in step S1960 and transmits the new operation parameter received from the SCF 1940 to the service application 1910 in step S1970. Then, the service application 1910 operates the user terminal by applying the received new operation parameter.

On the other hand, the user terminal information using the UE state analyzer can also be utilized in creating a policy for traffic offloading in an access network discovery service function (ANDSF).

20 is a diagram illustrating a method of utilizing SCF and ANDSF according to another embodiment of the present invention.

20, in step S2010, the user terminal 2010 transmits status information (information on the service application being executed, location, state of the WLAN) to the SCF 2020, Address or ID).

Then, the SCF 2020 searches the ANDSF 2030 based on this, and transmits the state information of the user terminal received from the user terminal 2010 to the ANDSF 2030.

The ANDSF 2030 receives only a few thousands of service applications that the user terminal 2010 can use and only generates a traffic offloading policy for a service application actually used by the user terminal in step S2030, The generated traffic offloading policy may be transmitted to the user terminal 2010 in step S2040.

21 is a block diagram illustrating an internal structure of a user terminal according to an embodiment of the present invention. As shown in FIG. 21, the terminal of the present invention may include a transmission / reception unit 2110, a storage unit 2120, and a control unit 2130. The transceiver 2110 can transmit and receive signals to and from the RAN node (base station). The signal may include control signals, data, and the like.

The storage unit 2120 may store various programs required for the operation of the user terminal. In particular, the storage unit 2120 according to an exemplary embodiment of the present invention may store information on whether a packet filter received from the core network node and whether to mark congestion information per packet included in the packet filter is required.

The controller 2130 controls the signal flow between each block for operation of the user terminal of the present invention. More specifically, the control unit 2130 can detect that packet filter information transmitted from the PDN gateway is received from the base station. When a packet to be transmitted is generated, the controller 2130 can determine whether congestion information marking is necessary based on the packet filter. If it is determined that the congestion information marking is necessary as a result of the determination, the controller 2130 controls to transmit congestion information marking application information to the packet to be transmitted to the base station. In this case, the control unit 2130 may control the congestion information marking application information to be included in the hair or control field of the packet.

The packet filter includes information on whether congestion information marking is applied to matching IP flows.

22 is a block diagram illustrating an internal structure of a RAN node, i.e., a base station, according to an embodiment of the present invention. As shown in FIG. 22, the base station of the present invention may include a wire / wireless communication unit 2210, a storage unit 2220, and a control unit 2230. The wired / wireless communication unit 2210 may include a wireless communication unit for performing communication with the terminal, and a wired communication unit for performing communication with the nodes of the core network.

The storage unit 2220 may store various programs necessary for the operation of the base station. The storage unit 2220 according to the embodiment of the present invention may store information on whether the congestion information marking received from the core network node or the user terminal is applied.

The controller 2230 may control the signal flow between each block so that the base station operates according to an embodiment of the present invention.

The control unit 2230 according to an embodiment of the present invention may receive a message including congestion information marking application information from the core network node of the wireless communication system. The control unit 2230 may determine whether to mark the congestion state information on the packet based on the congestion information marking application information when receiving a packet from the user terminal. The control unit 2230 may control the congestion state information to transmit the marked data packet according to the determination.

In this case, the core network node may be a Mobility Management Entity (MME) or a policy charging and rules function (PCRF)

Meanwhile, according to the embodiment of the present invention, the control unit for the congestion congestion information marking may be a PDN (Packet Data Network) connection or an EPS (Evolved Packet System) bearer. If the unit of control for congestion information marking is a PDN connection, the congestion information marking application information may be received at the default bearer establishment step. On the other hand, when the control unit for the congestion information marking is the EPS bearer, the congestion information marking application information may be received in the EPS bearer setting or the EPS bearer modification step.

Meanwhile, the control unit 2230 according to another embodiment of the present invention may receive a packet including congestion information marking application information from the terminal and extract a header from the packet to determine whether congestion information marking is necessary. If the congestion information marking is required and the BS is in a congested state, the control unit 2230 can control the congestion state information to transmit the marked packet. In this case, the control unit 2230 may mark the congestion state information in the IP header or the GTP-U header.

According to the embodiment of the present invention described above, the congestion state can be effectively controlled.

Claims (22)

A method for congestion control of a base station in a wireless communication system,
Receiving a message including congestion information marking application information from a core network node of the wireless communication system;
Determining, when receiving a packet from a user terminal, whether the congestion state information marking is necessary for the packet based on the congestion information marking application information; And
And transmitting the marked data packet with the congestion state information according to the determination.
2. The method of claim 1,
Wherein the MME is a Mobility Management Entity (MME) or a policy charging and rules function (PCRF).
The method according to claim 1,
Wherein the unit of control for congestion information marking is a PDN (Packet Data Network) connection or an EPS (Evolved Packet System) bearer.
The method of claim 3,
If the unit of control for the congestion information marking is a PDN connection,
Wherein the congestion information marking application information is received in a default bearer setup step.
The method of claim 3,
If the control unit for the congestion information marking is an EPS bearer,
Wherein the congestion information marking application information is received in the EPS bearer setting or the EPS bearer modification step.
A method for transmitting congestion related information of a terminal in a wireless communication system,
Receiving packet filter information from a PDN gateway;
Determining whether congestion information marking is necessary based on the packet filter when a packet to be transmitted is generated; And
And if the congestion information marking is necessary, transmitting the congestion related information including the congestion information marking application information to the packet to be transmitted to the base station.
7. The apparatus of claim 6,
And information about whether or not the congestion information marking is applied to the IP flows matched to the arbitrary filter.
7. The method of claim 6,
And the congestion information marking application information is included in a hair or control field of the packet.
A method for congestion control of a base station in a wireless communication system,
Receiving a packet including congestion information marking application information from a terminal;
Extracting a header from the packet to determine whether congestion information marking is required; And
And if the congestion information marking is necessary and the base station is in a congested state, transmitting the marked packet with the congestion status information.
10. The method of claim 9,
IP header or the GTP-U header to the congestion control information.
10. The method of claim 9,
Further comprising the step of marking and transmitting the congestion state information for packets included in the same IP flow when receiving a packet set to require congestion information marking.
A base station for controlling congestion in a wireless communication system,
A wired / wireless communication unit for performing communication with a terminal or core network nodes; And
Receiving a message including congestion information marking application information from a core network node of the wireless communication system and determining whether the congestion state information marking is necessary for the packet based on the congestion information marking application information upon receiving a packet from the user terminal And a controller for controlling to transmit the marked data packet with the congestion state information according to the determination.
13. The network node of claim 12,
Characterized in that the base station is a Mobility Management Entity (MME) or a Policy charging and rules function (PCRF).
13. The method of claim 12,
Wherein the unit of control for congestion information marking is a Packet Data Network (PDN) connection or an Evolved Packet System (EPS) bearer.
15. The method of claim 14,
If the unit of control for the congestion information marking is a PDN connection,
Wherein the congestion information marking application information is received in a default bearer setup step.
15. The method of claim 14,
If the control unit for the congestion information marking is an EPS bearer,
Wherein the congestion information marking application information is received in the EPS bearer setup or the EPS bearer modification step.
A terminal for transmitting congestion related information in a wireless communication system,
A transmission / reception unit for transmitting / receiving signals to / from a base station; And
PDN gateway, and determines whether congestion information marking is necessary based on the packet filter when a packet to be transmitted is generated. When the congestion information marking is required, the packet to be transmitted includes information on congestion information marking application, And a control unit for controlling the terminal to transmit the data.
18. The apparatus of claim 17,
And information about whether to apply congestion information marking to IP flows matched to any filter.
18. The apparatus of claim 17,
And controls to include the congestion information marking application information in a hair or control field of the packet.
A base station for controlling congestion in a wireless communication system,
A wired / wireless communication unit for performing communication with a terminal or core network nodes; And
Receiving a packet including congestion information marking application information from a terminal, extracting a header from the packet to determine whether congestion information marking is necessary, and if the congestion information marking is necessary and the base station is in a congested state, And control to transmit the marked packet.
21. The apparatus of claim 20,
IP header or GTP-U header of the congestion state information.
21. The apparatus of claim 20,
And controls to mark and transmit the congestion state information for packets included in the same IP flow when receiving a packet set to require congestion information marking.

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