KR102232787B1 - Method and apparatus for controlling service continuity in mobile communication systems - Google Patents

Abstract

An embodiment of the present invention provides a method and apparatus for controlling service continuity when a terminal is receiving a specific service in a wireless communication system. An embodiment of the present specification provides a control method and apparatus for supporting service continuity when a handover occurs while a user terminal is receiving a service having a specific QoS requirement. An embodiment of the present invention provides a method and apparatus for operating a core network node, a base station, and a terminal to support service continuity when a handover occurs.

Description

Method and apparatus for controlling service continuity in wireless communication system {METHOD AND APPARATUS FOR CONTROLLING SERVICE CONTINUITY IN MOBILE COMMUNICATION SYSTEMS}

Embodiments of the present specification relate to a method and apparatus for controlling service continuity when a terminal is receiving a specific service in a wireless communication system. In addition, an embodiment of the present specification relates to a control method and apparatus for supporting service continuity when a handover occurs while a user terminal is receiving a service having a specific QoS requirement.

In general, wireless communication systems have been developed to provide voice services while ensuring user activity. However, wireless communication systems are gradually expanding their range to not only voice but also data services, and have developed to the extent that they can provide high-speed data services. However, in a wireless communication system in which a service is currently provided, a lack of resources and users request a higher speed service, and thus a more advanced wireless communication system is required.

As one of the systems being developed as a next-generation wireless communication system in response to these demands, standard work for Long Term Evolution (LTE) is in progress in The 3rd Generation Partnership Project (3GPP). LTE is a technology that implements high-speed packet-based communication with a transmission rate of up to 100 Mbps. To this end, various methods have been discussed, for example, a method of reducing the number of nodes located on a communication path by simplifying the structure of a network, or a method of making wireless protocols as close to a wireless channel as possible.

An embodiment of the present invention is to provide a method and apparatus for controlling service continuity when a terminal is receiving a specific service in a wireless communication system. In addition, an embodiment of the present invention is to provide a control method and apparatus for supporting service continuity when a handover occurs while a user terminal is receiving a service having a specific QoS (Quality of Service) requirement.

According to an embodiment of the present invention, in a method for supporting handover of a core network node, receiving a handover request including a handover target base station identifier for a terminal, the handover target Determining whether the base station supports the QoS (Quality of Service) condition for the service currently being used by the UE, and if the handover target base station does not support the QoS condition for the service currently being used by the UE, the currently being used It provides a method comprising the step of mapping QCI for service and transmitting a handover progress message including the QCI mapping information to a handover target core network node of the terminal.

In addition, according to an embodiment of the present invention, in an apparatus of a core network node for handover, a communication unit communicating with at least one network node and a handover target base station identifier for the terminal are included. A handover request is received, the handover target base station determines whether the terminal supports a QoS (Quality of Service) condition for a service currently being used by the terminal, and the handover target base station is used for the service currently being used by the terminal. If the QoS condition is not supported, a control unit that maps QCI for the currently used service and controls to transmit a handover progress message including the QCI mapping information to a handover target core network node of the terminal. It provides an apparatus comprising the.

In addition, according to an embodiment of the present invention, in a method for supporting handover of a base station, determining whether handover is required for a user terminal using a specific bearer, and when it is determined that handover is necessary, from a list of neighboring base stations It provides a method comprising the steps of selecting a handover target base station supporting the specific bearer and performing a handover procedure for the terminal with respect to the selected handover target base station.

In addition, according to an embodiment of the present invention, in an apparatus of a base station for supporting handover, it is determined whether handover is necessary for a communication unit communicating with at least one network node and a user terminal using a specific bearer, and If it is determined that over is necessary, including a control unit for selecting a handover target base station supporting the specific bearer from a neighbor base station list, and controlling the selected handover target base station to perform a handover procedure for the terminal. It provides a device characterized by.

In addition, according to an embodiment of the present invention, in the handover method of the terminal, communicating with a base station using a specific bearer, reporting a cell measurement result to the base station, and based on the measurement result, the And receiving a handover request message including information about a handover target base station from a base station, wherein the handover target base station supports the specific bearer being used by the mobile station.

In addition, according to an embodiment of the present invention, in the device of the terminal for handover,

Communicates with a base station using a communication unit that communicates with at least one network node and a specific bearer, reports a cell measurement result to the base station, and includes the handover target base station information based on the measurement result from the base station And a control unit for controlling to receive a handover request message, wherein the handover target base station supports the specific bearer being used by the terminal.

In addition, according to an embodiment of the present invention, in a method for supporting handover of a core network node, determining whether a horse uses a bearer having a specific QCI (QoS Class Identifier) value, and the terminal is preset If a bearer having a specific QCI value is being used, generating handover restriction information for the terminal and transmitting the generated handover restriction information to a serving base station of the terminal, the handover restriction information Provides a method characterized in that the terminal includes information on at least one neighboring base station capable of supporting a bearer having the specific QCI value.

In addition, according to an embodiment of the present invention, in an apparatus of a core network node for supporting handover, a communication unit and a terminal communicating with at least one network node have a specific QCI (QoS Class Identifier) value. Determine whether to use a bearer, and if the terminal is using a bearer having a preset specific QCI value, it generates handover restriction information for the terminal, and transmits the generated handover restriction information to the serving base station of the terminal. It provides an apparatus comprising a control unit for controlling to be controlled, wherein the handover restriction information includes information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal.

In addition, according to an embodiment of the present invention, in a method for supporting handover of a base station, communicating with a terminal using a bearer having a specific QCI value, and receiving handover restriction information for the terminal from a core network node. It provides a method comprising the step of receiving, determining whether handover is required for the terminal, and selecting a base station to be handover for the terminal based on the received handover restriction information.

In addition, according to an embodiment of the present invention, in an apparatus of a base station for supporting handover, a communication unit communicating with at least one network node and a bearer having a specific QCI value are used to communicate with the terminal, and the core network A control unit that receives handover restriction information for the terminal from a node, determines whether handover is required for the terminal, and controls to select a base station for handover to the terminal based on the received handover restriction information. It provides an apparatus comprising the.

According to an embodiment of the present invention, when handover is required for a user terminal having a specific QoS requirement, QoS for a service is limited by limiting the candidates of the handover target base station or region to those that can satisfy the same QoS requirements. It can be ensured on an ongoing basis.

According to an embodiment of the present invention, when a handover is required for a user terminal having a specific QoS requirement, when the target base station or area cannot satisfy the same QoS requirements, QoS that can be supported by the target base station or area It converts to the most similar QoS among them so that service continuity can be guaranteed with minimal service quality degradation.

1 is a diagram showing the structure of a communication system according to an embodiment of the present specification.
2 is a table showing QoS parameters that can be used in an operator network.
3 is a diagram illustrating an operation of an operator network node according to an embodiment of the present invention.
4 is a diagram showing the operation of an operator network node according to a second embodiment of the present invention.
5 is a diagram showing information exchange between base stations.
6 is a diagram illustrating an operation of an operator network node according to a third embodiment of the present invention.
7 is a diagram illustrating an operation of an operator network node occurring when a user terminal switches from an idle mode to a connected mode according to a fourth embodiment of the present invention.
8 is a diagram illustrating a core network node according to an embodiment of the present invention.
9 is a diagram illustrating a base station according to an embodiment of the present invention.
10 is a diagram illustrating a terminal according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to more clearly convey the gist of the present invention by omitting unnecessary description.

For the same reason, some elements in the accompanying drawings are exaggerated, omitted, or schematically illustrated. In addition, the size of each component does not fully reflect the actual size. The same reference numerals are assigned to the same or corresponding components in each drawing.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

At this time, it will be appreciated that each block of the flowchart diagrams and combinations of the flowchart diagrams may be executed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates a means to perform functions. These computer program instructions can also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory It is also possible for the instructions stored in the flow chart to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block(s). Since computer program instructions can also be mounted on a computer or other programmable data processing equipment, a series of operating steps are performed on a computer or other programmable data processing equipment to create a computer-executable process to create a computer or other programmable data processing equipment. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block(s).

In addition, each block may represent a module, segment, or part of code that contains one or more executable instructions for executing the specified logical function(s). In addition, it should be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order depending on the corresponding function.

In this case, the term'~ unit' used in this embodiment refers to software or hardware components such as FPGA or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. Components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further separated into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card.

In the following description of embodiments of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In addition, in describing the embodiments of the present invention in detail, the basic 3GPP (Third Generation Partnership Project) LTE system will be the main target, but the embodiments of the present invention are other communication/computer systems having a similar technical background and system type. Also, it can be applied within a range not significantly departing from the scope of the present invention, which will be possible by the judgment of a person skilled in the technical field of the present invention.

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, ENB (RAN node) may be replaced with RNC/BSC, S-GW may be omitted or included in SGSN, and P-GW may correspond to GGSN. In addition, the EPS bearer concept of the LTE system may correspond to the PDP context of the UTRAN/GERAN system.

When a handover occurs while a user terminal is receiving a service having a specific QoS requirement, it is necessary to keep the service that the user terminal was receiving. If an area subject to handover does not have the same QoS requirements, it is difficult to support service continuity for a user terminal. If service continuity is not supported when a handover occurs in the user terminal, the quality of service perceived by the user is deteriorated. In particular, when the service is a public safety network service or an emergency service, basic requirements of the service cannot be satisfied.

In an embodiment of the present invention, in order to satisfy the requirements of such a communication system, a control method for supporting service continuity when a handover occurs while a user terminal is receiving a service having a specific QoS (Quality of Service) requirement. And the device will be described.

1 is a diagram showing the structure of a communication system according to an embodiment of the present specification. According to an embodiment, the communication system may be a mobile communication system based on LTE.

Referring to Figure 1, as shown in the radio access network of the LTE mobile communication system is a next-generation base station (Evolved Node B, EUTRAN, hereinafter referred to as ENB or Node B) 130 and MME (Mobility Management Entity) 150, and It is composed of S-GW (Serving-Gateway) 140.

The user equipment (User Equipment, hereinafter referred to as UE) 100 accesses an external network through ENB 130 and S-GW 140 and P-GW (PDN-Gateway) 160. In order for the user terminal to transmit and receive data through the PGW, a PDN connection must be created, and one PDN connection may include one or more EPS bearers.

The AF (Application Function) 110 is a device that exchanges application-related information with a user at an application level.

The PCRF 120 is a device that controls a user's QoS (Quality of Service)-related policy, and the PCC (Policy and Charging Control) rule corresponding to the policy is transmitted to the P-GW 160 Is 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 to the existing RNC/BSC.

In LTE, since all user traffic, including real-time services such as VoIP (Voice over IP) through Internet protocol, is serviced through a shared channel, a device that collects and schedules status information of the UEs 100 is required. ENB 130 is in charge of this.

The S-GW 140 is a device that provides a data bearer, and creates or removes a data bearer under the control of the MME 150.

The MME 150 is a device in charge of various control functions, and one MME 150 may be connected to a plurality of base stations.

The PCRF (Policy Charging and Rules Function) 120 is an entity that collectively controls QoS and billing for traffic.

2 is a table showing QoS parameters that can be used in an operator network.

Referring to FIG. 2, QoS parameters are classified according to QCI (QoS Class Index), and resource type, priority, PDB (Packet Delay Budget), and packet error rate for each QCI. loss rate), and representative services are defined. For example, the EPS bearer using QCI No. 1 has a low PDB value and is used for a service having a relatively high priority, for example, a voice call service.

QCI 65 is generally used for MCPTT (Mission Critical Push To Talk) voice service, and can be used to provide public safety services in emergency or disaster situations. Depending on the purpose of the service, the EPS bearer for MCPTT using QCI 65 has a low priority and a very small PDB value.

On the other hand, in describing the embodiments of the present invention, it will be considered that the EPS bearer for the MCPTT/nMCPTT service uses 65/66 as the QCI value, but this is for convenience of explanation, and the main point of the embodiments of the present invention May be applied as it is even when the EPS bearer for the MCPTT/nMCPTT service uses a different QCI value, for example 11/12.

The specific problem situation is as follows. The user terminal is receiving a service with specific QoS requirements (ie, has an EPS bearer for a specific QCI). At this time, although handover has occurred according to the location or channel state of the user terminal, it may not be possible to support the EPS bearer having the QCI in the base station or region (cell) that may be the target of the handover. For example, the user terminal is using the EPS bearer for MCPTT using QCI 65 in the E-UTRAN network, but handover has occurred, and the base station or area (cell) that can be the target of the handover in the vicinity is the UTRAN network. However, in the UTRAN network, there may be a case in which the EPS bearer with a QCI of 65 cannot be supported. In this case, since the EPS bearer using QCI 65 cannot be used after handover, it is difficult to continuously support the service.

In an embodiment of the present invention, in order to solve the above problem, when a handover occurs for a user terminal having a service having a specific QoS requirement (ie, an EPS bearer having a specific QCI), If the target base station or region (cell) candidates cannot support the EPS bearer having the QCI, the core network performs mapping to the QCI having the QoS parameter most similar to the existing QoS parameter, and accordingly, the EPS bearer context as a new QCI. It is to provide the service continuously by updating.

On the other hand, in the drawings and descriptions of the embodiments of the present invention, it will be assumed that the service used by the user terminal is MCPTT (that is, when the EPS bearer having a QCI of 65 is used). This is to describe an operation based on a service to be possessed, and the main point of the present embodiment is not limited to an MCPTT service and an EPS bearer having a QCI of 65.

3 is a diagram illustrating an operation of an operator network node according to an embodiment of the present invention. Referring to FIG. 3, the communication system includes a user terminal (UE, 310), a base station (eNB, 320), a radio network controller (RNC, 330), and a mobility management entity (MME, 340). And a serving GPRS support node (SGSN) 350. In the diagram of the embodiment, the original base station is set to eNB, the handover target base station is RNC, the original core network node is MME, and the handover target core network node is set to SGSN. It is not limited to this. Depending on the characteristics of the network (eg, E-UTRAN or UTRAN), the source base station and the handover target base station may be eNB, RNC, and BSC. In addition, depending on the characteristics of the network, the core network node and the handover target core network node may be MME or SGSN.

The user terminal 310 is receiving a service having a specific quality of service (QoS) requirement, and thus has an EPS bearer having a specific QCI (QoS Class Identifier) (S310). In one embodiment of the present invention, the service may be an MCPTT or a Non Mission Critical Push To Talk Voice (nMCPTT) service. Therefore, the QCI for the service may be 65 or 66.

The original base station (eNB or RNC/BSC, 320) recognizes that a handover is required for the user terminal. The original base station sends a handover request message (Handover Required) to the core network node (MME or SGSN, 340), and this message includes the identifier of the base station 330 or the region (cell) to be handover ( S320).

After receiving the handover request, the core network node (MME or SGSN, 340) checks the service being used by the user terminal or the EPS bearer context of the user terminal (S330). In addition, the core network node 340 is based on the identifier information of the base station 330 or the region (cell) to be handover received from the original base station 310, in the handover target base station or region (cell). It is checked whether the user terminal 310 supports the QoS requirement for the service being used or the QCI of the EPS bearer to support it (S330).

In this embodiment, the service being used by the user terminal 310 may be MCPTT or nMCPTT, and therefore, the QCI of the EPS bearer may be 65 or 66. In addition, in this embodiment, the core network node 340 may check whether QCI 65 or 66 is supported in the handover target base station 330 or the region (cell). If the QoS requirement or QCI for the service of the user terminal 310 is not originally supported in the base station or region (cell) to be handover, the core network node 340 performs a QoS mapping operation. In this case, the QoS mapping operation may be performed according to the local configuration of the core network node.

In the mapping operation, the core network node 340 performs mapping to a QCI having a QoS parameter most similar to an existing QoS parameter for a service currently being used by the terminal. This is to continuously provide services by updating the EPS bearer context with QCI. The QoS parameter may include a QoS class indicator (QCI), an allocation and retention priority (ARP), a guaranteed bit rate (GBR), or an MBR. For example, in this embodiment, the configuration information of the core network node 340 is set so that an EPS bearer with a QCI of 65 is mapped to an EPS bearer with a QCI of 1, and an EPS bearer with a QCI of 64 is mapped to an EPS bearer with a QCI of 1. It can be (S330). This means that the packet error rate of the EPS bearer with QCI of 1 and the EPS bearer with QCI of 65 is the same, and although the PDB of the EPS bearer with QCI of 1 is greater than the PDB of the EPS bearer with QCI of 65, the EPS bearer with QCI of 1 This is because the priority of is the highest among GBR bearers excluding EPS bearers of QCI 65.

The original core network node 340 may transmit a message for handover proceeding to the handover target core network node 350. The message for proceeding the handover may be a Forward Relocation Request message. This message contains the EPS bearer context according to the result mapped in the previous step S330.

The handover target core network node 350 may transmit a message for requesting a handover to the handover target base station 330. The message for handover may be a Relocation request or a Handover request message. This message contains the EPS bearer context according to the result mapped in step S330.

The handover target base station node 330 transmits a response message to the handover request to the handover target core network node 350. This message contains the EPS bearer context according to the result mapped in the previous step S330.

If it is determined in step S330 that the original core network node 340 supports the service QoS requirements for the handover user terminal 310 or the EPS bearer to support it, the process proceeds to step S340 without a separate mapping operation, and the hand A message for over-progress can be transmitted.

Meanwhile, in the above embodiment, it has been described that the original core network node 340 performs mapping for QoS parameters. However, as a variation of the above embodiment, the mapping for QoS parameters may be performed in the core network node 350 to be handover. That is, in S330 of FIG. 3, the original core network node 340 may transmit a message for handover progress to the handover target core network node 350 based on the original EPS bearer context without performing QoS mapping. The message for proceeding the handover may be a Forward Relocation Request message. The handover target core network node 350 receiving the message for the handover process may support QoS parameters for the EPS bearer received from the original core network node 340 in the handover target base station or region (cell). Judge whether or not. That is, it is determined whether the handover target base station or region (cell) can support the QoS requirements for the service being used by the handover target user terminal 310 or the EPS bearer for supporting the QoS requirements. If it is determined that it is not supported, the handover target core network node 350 may perform QoS mapping. The QoS mapping operation is the same as described in S330. After mapping, it may operate as described in S350 and S360.

Meanwhile, when the EPS bearer context for the user terminal is changed according to the above embodiment, a process for modifying the EPS bearer context may be additionally performed. In order to modify the EPS bearer context, the core network node may transmit a UE context setup message for the changed EPS bearer context to the base station. The base station and the terminal may perform the RRC connection reconfiguration procedure based on the UE context setup message, and through this, the changed EPS bearer context may be applied.

In addition, in the above embodiment, when a network to which the user terminal originally received a service or a network that is a target of handover is a UTRAN or GERAN, a PDP context may be used instead of an EPS bearer.

In the second embodiment of the present invention, when a handover occurs for a user terminal having a service having a specific QoS requirement (ie, having an EPS bearer having a specific QCI), a target base station or a region (cell) is selected. This is a method of excluding base stations or regions (cells) that cannot support the EPS bearer having the QCI.

4 is a diagram showing the operation of an operator network node according to a second embodiment of the present invention. In this drawing and its description, it will be assumed that the service used by the user terminal 410 is MCPTT (ie, the EPS bearer with a QCI of 65 is used), but this is based on a service having a specific QoS requirement. It is to explain one operation, the main point of the present embodiment is not limited to the MCPTT service and the EPS bearer QCI of 65.

The user terminal 410 is using the MCPTT or nMCPTT service, and therefore has an EPS bearer with a QCI of 65 or 66 (S410).

The base station 420 may perform measurement to measure the channel state of the user terminal (S420).

The base station 420 determines that handover is necessary based on the measurement result, and selects a base station or region (cell) to be handover (S430). When the user terminal 410 is using an EPS bearer having a preset specific QCI value, the base station 420 searches a list of neighboring cells, and the base station or area (cell) that is a handover target supporting the specific QCI value. You can choose. For example, when the user terminal 410 is using the EPS bearer of QCI 65 or 66, the base station 420 checks whether the EPS bearer of QCI 65 or 66 is supported by searching NCL (Neighbor Cell List). . The base station 420 may perform a handover process by selecting a base station or region (cell) capable of supporting an EPS bearer of QCI 65 or 66. That is, in this embodiment, the base station 420 is storing information indicating whether a neighboring base station or region (cell) can support an EPS bearer of QCI 65/66 in the NCL, and selects a target for handover based on this. do. Whether the QCI supports the EPS bearer of 65 or 66 may include determining whether to support the MCPTT or nMCPTT service.

Meanwhile, the neighboring base station information may be stored in order to determine whether the neighboring base station supports the EPS bearer having a QCI of 65 or 66. For example, information about neighboring base stations may be stored through information exchange between base stations as shown in FIG. 5.

Meanwhile, if any neighboring base station cannot support the EPS bearer having the same QCI value, the neighboring base station having the highest QoS similarity may be selected as the handover target base station. This can also be applied to the following third and fourth embodiments.

5 is a diagram showing information exchange between base stations. In this drawing and its description, it will be assumed that the service used by the user terminal is MCPTT (that is, when the EPS bearer with QCI is 65) is assumed, but this is an operation based on a service having specific QoS requirements. It is for the purpose of explanation, and the main point of this embodiment is not limited to the MCPTT service and the EPS bearer having a QCI of 65.

If the base station 510 needs X2 connection with another base station 520, it transmits an X2 configuration request to the base station (S510). This message includes information indicating whether the MCPTT or nMCPTT service can be supported, that is, whether the EPS bearer of QCI 65 or 66 is supported.

The neighboring base station 520 receiving this stores whether or not the other base station supports MCPTT or nMCPTT in the NCL (S520).

The neighboring base station 520 transmits a response message to the request to the base station 510 (S530). The response message may be an X2 configuration response message. In this case, the X2 configuration response message may include information indicating whether the adjacent base station 520 supports MCPTT or nMCPTT.

The base station 510 stores whether the adjacent base station supports MCPTT or nMCPTT in the NCL.

In the third embodiment of the present invention, when a handover occurs for a user terminal having a service having a specific QoS requirement (that is, having an EPS bearer having a specific QCI), the handover target base station or area (cell) This is a method of excluding those that cannot support the EPS bearer having the QCI when selecting. The difference from the second embodiment is that the base station node does not perform the operation based on the NCL, but performs the operation based on the Handover Restriction List (HRL) received from the MME (or SGSN).

6 is a diagram illustrating an operation of an operator network node according to a third embodiment of the present invention. In this drawing and its description, it will be assumed that the service used by the user terminal is MCPTT (that is, when the EPS bearer with QCI is 65) is assumed, but this is an operation based on a service having specific QoS requirements. It is for the purpose of explanation, and the main point of this embodiment is not limited to the MCPTT service and the EPS bearer with QCI of 65.

The user terminal 610 is registered in the operator network, and has not established an EPS bearer for MCPTT or nMCPTT during the basic registration procedure (attach) (S610).

The user terminal 610 and the operator network set an EPS bearer for MCPTT or nMCPTT service, that is, an EPS bearer having a QCI of 65 or 66 according to a service request (S620).

The core network node (MME or SGSN, 630) of the operator network has set the EPS bearer for the user terminal 610, but it can be seen that the QCI is 65 or 66 (S630). Therefore, when generating a Handover Restriction List (HRL) for a user terminal, a base station or region (cell) that does not support MCPTT or nMCPTT among the base stations or regions (cells) subject to handover is excluded (S630). That is, a base station or region (cell) that does not support an EPS bearer having a QCI of 65 or 66 is set to be excluded from the target of handover. For example, if the UTRAN is considered as a handover target for the user terminal 610, but MCPTT or nMCPTT is not supported in the UTRAN, the core network node 630 is the forbidden RAT (Radio Access Technology) of the HRL. Is set.

The HRL generated by the core network node 630 is transmitted to the base station 620 (S640). The generated HRL may be transmitted through an S1_AP or Iu message. The message may be one of Downlink NAS Transport and E-RAB setup request. The base station 620 may store the received HRL.

When a handover is required, the base station 620 selects a base station or region (cell) to be a handover target based on the HRL received from the core network node 620 (S650).

7 is a diagram illustrating an operation of an operator network node that occurs when a user terminal switches from an idle mode to a connected mode according to a fourth embodiment of the present invention. In this drawing and its description, it will be assumed that the service used by the user terminal is MCPTT (that is, when the EPS bearer with QCI is 65) is assumed, but this is an operation based on a service having specific QoS requirements. It is for the purpose of explanation, and the main point of this embodiment is not limited to the MCPTT service and the EPS bearer with QCI of 65.

Referring to FIG. 7, the user terminal 710 transmits a request message and a service request message to the core network node 730 to switch from an idle state to a connected state for receiving a service (S710).

The core network node (MME or SGSN, 730) of the operator network can know that the user terminal has an EPS bearer having a QCI of 65 or 66 according to the EPS bearer context of the user terminal 710 (S720). In this case, when generating the HRL for the user terminal 710, the core network node 730 does not support MCPTT or nMCPTT among the base stations or regions (cells) subject to handover, that is, the QCI is 65 or 66. A base station or region (cell) that does not support the EPS bearer is set to be excluded from the target of handover (S720). For example, if the UTRAN is considered as a handover target for the user terminal, and MCPTT or nMCPTT is not supported in the UTRAN, the core network node configures the UTRAN with the forbidden radio access technology (RAT) of the HRL.

The HRL generated by the core network node 730 is transmitted to the base station 720 through an S1_AP or Iu message (S730). The message may be an initial context setup request message.

When a handover is required, the base station 720 selects a base station or region (cell) to be a handover target based on the HRL received from the core network node 730 (S740).

On the other hand, in the fifth embodiment of the present invention, a method of reducing the battery consumption of the user terminal and increasing the availability of the operator network is added by determining the access mode and detailed access state of the user terminal in consideration of the traffic characteristics of the user terminal. Presented as. More specifically, if the probability of subsequent data traffic transmission is low after the user terminal finishes transmitting and receiving data, this may be notified to the base station control node to cause a transition to a low battery consumption state. If the embodiments of the present invention are applied to a user terminal accessing the LTE network, the layer at which the operation is performed is changed (for example, the NAS transmits a request message to change the connection state instead of RRC), or used for a request. The message to be changed (for example, a UE Assistance Information message or an RRC Release Request message instead of the SCRI message of the RRC layer), or some steps/operations in the embodiments of the present invention may be omitted or the order may be changed.

If the user terminal uses the E-UTRAN network, the user terminal may transmit a request message for changing the connection state to the base station. This operation, according to embodiments of the present invention, requires that the upper layer (traffic monitoring unit, Application Synchronizer, or NAS layer) terminates the traffic transmission/reception, the PS data session is terminated, user inactivity, or RRC connection release. This may be performed when at least one or more of the information informing is notified to the communication control unit (RRC layer).

In the upper layer, it may be determined by embodiments of the present invention to determine whether to inform one or more of the above information. The user terminal can use the UE Assistance Information message as a request message, and in this message, among information indicating that traffic transmission/reception has ended, PS data session has ended, RRC connection release is required, user inactivity, or low power consumption is required. One or more may be included.

Upon receiving the message including the information from the user terminal, the base station may transmit an operation for releasing the RRC connection to the user terminal, that is, an RRC connection release message to the user terminal. In addition, the base station may transmit a request message to release the UE context to the MME. Meanwhile, the UE Assistance Information may be replaced with an RRC connection release request message.

Alternatively, the information may be included in a header or a control element used when the user terminal transmits a user plane data packet, not a separate control message transmitted by the user terminal to the base station. Meanwhile, the base station may delay performing the operation of releasing the RRC connection until transmission and reception of user plane data to the user terminal are terminated.

As a variation of the always-on embodiment, if the user terminal uses the E-UTRAN network, the user terminal may transmit a request message for changing the connection state to the MME. This operation is, according to embodiments of the present invention, at least one of information indicating that the upper layer (traffic monitoring unit) has ended traffic transmission/reception, the PS data session has ended, user inactivity, or RRC connection release is required. This can be performed when notifying the communication control unit (NAS layer).

In the upper layer, it may be determined by embodiments of the present invention to determine whether to inform one or more of the above information. The user terminal can use a NAS message as a request message, and in this message, one or more of information indicating that traffic transmission/reception has ended, PS data session has ended, RRC connection release is required, user inactivity, or low power consumption is required. May be included.

In one embodiment of the present invention, the NAS message may be an EMM status message, indicating that the traffic transmission/reception has ended, PS data session has ended, RRC connection release is required, user inactivity, or low power consumption is required. The information may be included in the EMM cause information element.

Upon receiving the NAS message including the information from the user terminal, the MME performs an operation for releasing the RRC connection to the user terminal. Release of the RRC connection to the user terminal may mean that the MME releases a logical connection related to the user terminal. To this end, the MME may transmit a UE context release command message to the base station. This message may include one of information indicating that traffic transmission/reception has ended due to connection release, PS data session has ended, RRC connection release is required, user inactivity, or low power consumption is required.

If the base station receives the UE context release command message from the MME, the base station performs an operation to release the RRC connection to the user terminal. If the message received by the base station contains one of information indicating that the traffic transmission/reception has ended, the PS data session has ended, RRC connection release is required, user inactivity, or low power consumption is required, the base station is the user terminal. After waiting until all user plane data transmission and reception for the user plane is finished, an operation for releasing the RRC connection may be performed.

Next, a sixth embodiment of the present invention will be described. When the operator network provides the RAN rule for WLAN offloading control for the user terminal, the user terminal is the WLAN through a System Information Block (SIB) or RRC message (RRC Connection Reconfiguration) transmitted by a base station (E-UTRAN or UTRAN). Offloading control information (ie, RAN rule) may be received. The WLAN offloading control information includes a list of WLANs that the user terminal can access, various parameters that can be used when the user terminal selects a WLAN or determines whether to offload traffic (signal strength or congestion status, Offloading Preference Indicator, etc.), WLAN Timer values to be applied when performing an offloading operation are included.

However, the user terminal may camp on the E-UTRAN or UTRAN to receive a service, receive the information, and then move to a base station or area that does not provide the information. For example, a user terminal receives a service from a Release-12 base station capable of transmitting a System Information Block (SIB) or RRC message including the WLAN offloading control information, and then goes to the area of the Release-11 base station that does not have the information providing function. There may be cases of movement. In addition, there may be a case in which the user terminal receives a service from the E-UTRAN/UTRAN base station capable of transmitting the SIB or RRC message including the WLAN offloading control information and then moves to the area of the GERAN base station.

In the above situation, since the user terminal cannot receive WLAN offloading control information from the base station, it may be unclear how to perform the WLAN offloading operation.

In order to solve the above problem, in the sixth embodiment of the present invention, when the base station capable of providing WLAN offloading control information provides WLAN offloading control information to a user terminal through an SIB or RRC message, WLAN offloading control information is provided. It is characterized by including information that can be used in an area that cannot be provided.

That is, WLAN offloading control information (wlan-offloadcommon IE included in the SIB17 message or wlan-OffloadDedicated IE included in the RRC connection reconfiguration message) provided by the base station to the user terminal is Include condition information. More specifically, the WLAN offloading control information includes an applicable RAT (UTRAN/GERAN) condition or an applicable location identifier (Tracking area ID, Routing area ID, base station ID, or cell ID) condition. For example, if the user terminal includes a GERAN as applicable RAT information in the wlan-offloadDedicated IE received from the base station, the user terminal offloads WLAN according to the control information included in the wlan-offloadDedicated IE received from the GERAN area. You can perform the operation.

Another modification to the embodiment of the present invention is in the mobilityControlInfo IE of the RRC connection release message for switching the user terminal to another RAT or cell or the RRC connection reconfiguration message for handover, the user terminal has finished switching or handover. It includes WLAN offloading control information that can be applied later.

That is, when the user terminal needs to switch/handover to another RAT, base station or region, the base station controls WLAN offloading that must be applied in the target base station or region to a command message (the RRC connection release or RRC connection reconfiguration) sent to the user terminal. Include information (wlan-offloadDedicated IE or wlan-offloadCommon IE). The determination of whether to include the information in a message sent by the base station to the user terminal may be limited to a specific RAT or base station/area. That is, the base station may include the information only when a switching or handover operation to a specific RAT or base station/area is required for the user terminal. For example, the base station may transmit the WLAN offloading control information by including it in an RRC connection release message or an RRC connection reconfiguration message when the user terminal is switched to the GERAN region or is handed over.

The user terminal, if performing a WLAN offloading operation based on the WLAN offloading control information provided by the base station, and switching/handover to a base station or region that does not provide WLAN offloading control information, the stored When the applicable RAT condition or location condition is included in the WLAN offloading control information, it is determined whether this condition is satisfied. If the condition is satisfied, the user terminal can perform the WLAN offloading operation by continuing to use the stored WLAN offloading information (ie, received from the previous base station).

Meanwhile, if the user terminal receives WLAN offloading control information (wlan-offloadDedicated IE or wlan-offloadCommon IE) to be used in the target base station or area in the RRC connection release or handover command message (RRC connection reconfiguration message), the user terminal When the switching or handover process is completed, the WLAN offloading operation may be performed based on the received WLAN offloading control information. The WLAN offloading control information transmitted to the user terminal during the RRC connection release process or handover process may be information that is limitedly applied to a target RAT or a base station/area.

8 is a diagram illustrating a base station according to an embodiment of the present invention. The base station may be an eNB, an RNC or a BSC. Referring to FIG. 8, the base station 800 may include a communication unit 810 and a control unit 830. The communication unit 810 may communicate with at least one network node. The controller 830 may control the overall operation of the base station 800.

The controller 830 may control to perform a handover operation for a corresponding terminal based on QCI mapping information received from a core network node.

According to an embodiment of the present invention, the control unit 830 determines whether handover is necessary for a user terminal using a specific bearer, and if it is determined that handover is necessary, a hand supporting the specific bearer in a neighbor base station list An over-target base station may be selected, and the selected handover target base station may be controlled to perform a handover procedure for the terminal. At this time, the specific bearer may be a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service.

In addition, the control unit 830 may control to establish an X2 interface connection with at least one neighboring base station and update the neighboring base station list based on a message for setting the X2 interface connection. In this case, the message for setting up the X2 connection may include information indicating whether to support MCPTT or nMCPTT.

In addition, the control unit 830 communicates with the terminal using a bearer having a specific QCI value, receives handover restriction information for the terminal from a core network node, and determines whether handover is required for the terminal. , Based on the received handover restriction information, it is possible to control to select a base station for handover to the terminal. In this case, the handover restriction information may include information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal. In addition, the bearer having the specific QCI value may be a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service.

In the above, the configuration and function of the base station 800 have been described by dividing the blocks, but this is for convenience of description and the scope of the present invention is not limited thereto. In addition, the base station 800 may perform not only the operation described in FIG. 8 but also the operation of the base station according to the embodiment of the present invention described with reference to FIGS. 1 to 7.

9 is a diagram illustrating a core network node according to an embodiment of the present invention. The core network node may be an MME or SGSN. Referring to FIG. 9, the core network node 900 may include a communication unit 910 and a control unit 930. The communication unit 910 may communicate with at least one network node. The controller 930 may control the overall operation of the core network node 900.

According to an embodiment of the present invention, the control unit 930 receives a handover request including a handover target base station identifier for the terminal, and the handover target base station provides QoS (Quality of Service) condition, and if the handover target base station does not support the QoS condition for the service currently in use by the UE, the QCI for the service currently in use is mapped, and the handover of the UE It is possible to control to transmit a handover progress message including the QCI mapping information to an over-target core network node.

In addition, the control unit 930 may control the UE to map the QIC to QCI having a QoS parameter most similar to an existing QoS parameter for a service currently being used. In this case, the QCI mapping information may be used to form an EPS bearer between the handover target core network node and the handover target base station for a service currently in use for the terminal.

In addition, if the service currently being used by the terminal is MCPTT (Mission Critical Push To Talk Voice) or nMCPTT (Non Mission Critical Push To Talk Voice), the control unit 930 is an EPS (Evolved Packet System) bearer having a QCI value of 1. It can be controlled to map QCI.

In addition, the control unit 930 determines whether the terminal uses a bearer having a specific QCI (QoS Class Identifier) value, and if the terminal is using a bearer having a specific QCI value, handover restriction for the terminal It is possible to generate information and control to transmit the generated handover restriction information to a serving base station of the terminal. In this case, the handover restriction information may include information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal.

In addition, the control unit 930 may control a base station that does not support a bearer having the specific QCI value to be excluded from handover restriction information. In this case, the handover restriction information may be used by the serving base station to select a handover target base station when there is a handover request for the terminal.

In the above, the configuration and function of the core network node 900 have been described by dividing the blocks, but this is for convenience of description and the scope of the present invention is not limited thereto. In addition, the core network node 900 may perform not only the operation described in FIG. 9 but also the operation of the core network node according to an embodiment of the present invention described with reference to FIGS. 1 to 7.

10 is a diagram illustrating a terminal according to an embodiment of the present invention. Referring to FIG. 10, the terminal 1000 may include a communication unit 1010 and a control unit 1030. The communication unit 1010 may communicate with at least one network node. The controller 1030 may control the overall operation of the terminal 1000.

According to an embodiment of the present invention, the control unit 1030 may control to perform a handover procedure for a handover target base station based on QCI mapping information and handover restriction information exchanged between the base station and the core network node. Also, based on the new bearer configuration information, an RRC connection reconfiguration process may be performed.

In addition, the control unit 1030 communicates with a base station using a specific bearer, reports a cell measurement result to the base station, and includes the handover target base station information based on the measurement result from the base station. It can be controlled to receive an over request message. In this case, the handover target base station may support the specific bearer that the terminal is using.

In this case, the specific bearer may be a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service.

In the above, the configuration and function of the terminal 1000 have been described by dividing the blocks, but this is for convenience of description and the scope of the present invention is not limited thereto. In addition, the terminal 1000 may perform not only the operation described in FIG. 10 but also the operation of the terminal according to the exemplary embodiment of the present invention described with reference to FIGS. 1 to 7.

Although each embodiment of the present invention has been described with reference to the drawings above, this is for convenience of description, and each embodiment may be independently performed, and may be operated as a combination of different embodiments.

Meanwhile, in the present specification and drawings, a preferred embodiment of the present invention has been disclosed, and although specific terms are used, this is only used in a general meaning to easily describe the technical content of the present invention and to aid understanding of the present invention. It is not intended to limit the scope of the invention. In addition to the embodiments disclosed herein, it is apparent to those of ordinary skill in the art that other modified examples based on the technical idea of the present invention can be implemented.

Claims (32)

In the method for supporting handover of a core network node,
Receiving a handover request including a handover target base station identifier for the terminal;
Determining whether the handover target base station supports a quality of service (QoS) condition for a service currently being used by the terminal;
If the handover target base station does not support the QoS condition for the service currently being used by the UE, mapping QCI for the service currently being used; And
And transmitting a handover progress message including QCI mapping information to a handover target core network node of the terminal. The method of claim 1, wherein the mapping of the QCI comprises:
Mapping to QCI having the same QoS parameter as the QoS parameter for a currently used service, and when there are two or more QCIs having the same QoS parameter, mapping to the QCI having the highest priority. The method of claim 1, wherein the QCI mapping information is used to form an EPS bearer between the handover target core network node and the handover target base station for a service currently being used for the terminal. The method of claim 1, wherein the mapping of the QCI comprises:
If the service currently being used by the terminal is MCPTT (Mission Critical Push To Talk Voice) or nMCPTT (Non Mission Critical Push To Talk Voice), the method characterized in that the QCI value is mapped to an EPS (Evolved Packet System) bearer of 1. . In the device of a core network node for handover,
A communication unit communicating with at least one network node; And
Receiving a handover request including a handover target base station identifier for a terminal, determining whether the handover target base station supports a QoS (Quality of Service) condition for a service currently in use by the terminal, and the handover target If the base station does not support the QoS condition for the service currently in use by the mobile station, maps QCI for the service currently in use, and handover including QCI mapping information to the handover target core network node of the mobile station And a control unit for controlling to transmit a progress message. The method of claim 5, wherein the control unit,
In the case of mapping the QCI, mapping to QCI having the same QoS parameter as the QoS parameter for the currently used service, and when there are two or more QCIs having the same QoS parameter, controlling to map to the QCI having the highest priority Device characterized in that. The apparatus of claim 5, wherein the QCI mapping information is used to form an EPS bearer between the handover target core network node and the handover target base station for a service currently being used for the terminal. The method of claim 5, wherein the control unit,
In the case of mapping the QCI, if the service currently being used by the terminal is MCPTT (Mission Critical Push To Talk Voice) or nMCPTT (Non Mission Critical Push To Talk Voice), the QCI value is 1 as an EPS (Evolved Packet System) bearer. An apparatus for mapping QCI. In the base station handover support method,
Determining whether handover is required for a user terminal using a specific bearer;
If it is determined that handover is necessary, selecting a handover target base station supporting the specific bearer from a neighbor base station list; And
And performing a handover procedure for the terminal with respect to the selected handover target base station. The method of claim 9, wherein the specific bearer is a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. The method of claim 9,
Establishing an X2 interface connection with at least one neighboring base station; And
Further comprising the step of updating the neighboring base station list based on the message for X2 interface connection establishment,
The message for configuring the X2 interface connection, characterized in that it comprises information indicating whether to support MCPTT or nMCPTT. In the base station apparatus for handover support,
A communication unit communicating with at least one network node; And
Determine whether handover is necessary for a user terminal using a specific bearer, and if it is determined that handover is necessary, a handover target base station supporting the specific bearer is selected from a list of neighboring base stations, and the selected handover target base station And a controller for controlling to perform a handover procedure for the terminal. The apparatus of claim 12, wherein the specific bearer is a bearer supporting a Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. The method of claim 12, wherein the control unit,
Control to establish an X2 interface connection with at least one neighboring base station, and update the neighboring base station list based on a message for setting up an X2 interface connection,
The device, characterized in that the message for setting the X2 interface connection includes information indicating whether to support MCPTT or nMCPTT. In the terminal handover method,
Communicating with a base station using a specific bearer;
Reporting a cell measurement result to the base station; And
Receiving a handover request message including information about a base station to be handover from the base station based on the measurement result,
The method of claim 1, wherein the handover target base station supports the specific bearer in use by the terminal. The method of claim 15, wherein the specific bearer is a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. In the device of the terminal for handover,
A communication unit communicating with at least one network node; And
Controls to communicate with a base station using a specific bearer, report a cell measurement result to the base station, and receive a handover request message including information on a handover target base station based on the measurement result from the base station It includes a control unit,
The device, characterized in that the handover target base station supports the specific bearer in use by the terminal. The apparatus of claim 17, wherein the specific bearer is a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. In the method for supporting handover of a core network node,
Determining whether the terminal uses a bearer having a specific QCI (QoS Class Identifier) value;
If the terminal is using a bearer having a predetermined specific QCI value, generating handover restriction information for the terminal; And
Including the step of transmitting the generated handover restriction information to the serving base station of the terminal,
The handover restriction information includes information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal. The method of claim 19, wherein generating the handover restriction information comprises:
And excluding a base station that does not support a bearer having the specific QCI value from handover restriction information. The method of claim 19, wherein the handover restriction information,
When there is a handover request for the terminal, the serving base station is used to select a handover target base station. The method of claim 19, wherein the bearer having the predetermined specific QCI value is a bearer supporting a Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. In the device of a core network node for supporting handover,
A communication unit communicating with at least one network node; And
It is determined whether the UE uses a bearer having a specific QCI (QoS Class Identifier) value, and if the UE is using a bearer having a specific QCI value, handover restriction information for the UE is generated, and And a control unit for controlling to transmit the generated handover restriction information to a serving base station, wherein the handover restriction information includes information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal. Device characterized by. The method of claim 23, wherein the control unit,
And controlling to exclude a base station that does not support a bearer having the specific QCI value from handover restriction information. The method of claim 23, wherein the handover restriction information,
When there is a handover request for the UE, the serving base station is used to select a handover target base station. The apparatus of claim 23, wherein the bearer having the predetermined specific QCI value is a bearer supporting a Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. In the base station handover support method,
Communicating with a terminal using a bearer having a specific QCI value;
Receiving handover restriction information for the terminal from a core network node;
Determining whether handover is required for the terminal; And
And selecting a base station for handover to the terminal based on the received handover restriction information. 28. The method of claim 27, wherein the handover restriction information includes information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal. The method of claim 27, wherein the bearer having the specific QCI value is a bearer that supports Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service. In the base station apparatus for handover support,
A communication unit communicating with at least one network node; And
Communicates with a terminal using a bearer having a specific QCI value, receives handover restriction information for the terminal from a core network node, determines whether handover is required for the terminal, and based on the handover restriction information And a control unit for controlling to select a base station for handover to the terminal. The apparatus of claim 30, wherein the handover restriction information includes information on at least one neighboring base station capable of supporting a bearer having the specific QCI value to the terminal. The apparatus of claim 30, wherein the bearer having the specific QCI value is a bearer supporting a Mission Critical Push To Talk Voice (MCPTT) or Non Mission Critical Push To Talk Voice (nMCPTT) service.

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