JP2014230037A - Method and device for accessing multiple radio bearers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a mechanism of coordination between a multi-homing function at a base station side and bearer selection operation at a radio terminal side at the time of executing policy control to adaptively control a communication path in a radio network depending on a situation.SOLUTION: If a multi-homed base station with which a radio terminal 10 is communicating supports a plurality of cells capable of different RAT in an overlapping manner, the execution of bearer selection operation among a plurality of radio bearers connected with the plurality of cells is switched from the radio terminal 10 to the base station side, and thereby the bearer selection operation among the plurality of radio bearers simultaneously usable for the radio terminal 10 to connect with a radio network is shared and executed between the radio terminal 10 and the multi-homed base station.

Description

  The present invention relates to access to various wireless services, and more specifically, to a method and apparatus for appropriately accessing a plurality of different radio bearers that provide a plurality of different wireless services according to the situation.

  Various wireless communication services such as a 3G cellular mobile phone network such as wireless LAN, WiMAX, and UMTS or an LTE network correspond to a plurality of different wireless access technologies (RAT (Radio Access Technology)). The radio bearer provides a radio connection means for connecting to these various radio communication services and accessing from a user radio terminal (UE).

  A cellular radio network such as a UMTS network or an LTE network provides a radio network connection service to users through a single carrier network over a wide geographical area. On the other hand, in many cases, wireless access to a cellular wireless network is limited only to the wireless terminals of users who subscribe to the communication service provided by the cellular wireless network and is often provided free of charge. Communication charges are generally higher than On the other hand, a wireless LAN service that can be used by the general public has a low communication fee and a relatively stable communication speed. However, the wireless LAN service is limited to a narrow area where a good communication range is limited.

  As a usage mode of a wireless terminal in recent years, it is common to switch a wireless access network to be used between a cellular wireless network and a wireless LAN service according to a situation by a user himself / herself. In order to enable such usage of the wireless terminal, a multi-mode wireless terminal equipped with a plurality of wireless interface circuits respectively corresponding to a plurality of different RATs (for example, LTE, WiMAX, wireless LAN, etc.) is used. It is assumed that the user performs wireless network access. In this case, the multi-mode wireless terminal can establish a plurality of radio bearers connected to each of a plurality of different RATs that can be used simultaneously, and can execute simultaneous parallel radio transmission on the plurality of radio bearers. This is known as link aggregation. Further, as another aspect, the multi-mode wireless terminal can perform wireless communication by selectively switching the RAT to which one radio bearer is connected according to the situation between a plurality of different RATs that can be used simultaneously. This is called connection switching between different types of RATs. As described above, by distributing and controlling communication traffic of wireless terminals among a plurality of radio bearers connected to different RATs, aggregation of wireless bandwidth, communication load distribution among different RATs, flexible network availability, etc. The benefits of being able to be achieved.

  On the other hand, when a multi-mode wireless terminal communicates via a plurality of wireless communication paths corresponding to different RATs, communication is performed while taking into consideration the traffic load distribution status, congestion status or effective communication throughput on the wireless network side. In order to select an optimal RAT to be used, a policy control mechanism as described in Patent Document 1 is required. In other words, when the multi-mode wireless terminal selects the optimum RAT to be used for communication, the above-described aggregation of the wireless bandwidth, distribution of communication load among different types of RATs, flexible network availability, etc. In order to ensure that the benefits are not impaired by the operating conditions inside the wireless network, the entire end-to-end communication path that passes through the radio access network and the core network is adapted to RAT switching on the wireless terminal side. Optimization is also required. In order to optimize the entire end-to-end communication path, it is effective to introduce a policy control mechanism from the wireless network side. Specifically, for uplink and downlink traffic communicated by a wireless terminal, a mechanism for appropriately policy-controlling the communication traffic transfer path according to the situation is required in the local domain of the wireless network. Patent Document 1 describes a mechanism for controlling a traffic communication path based on a communication path control policy set on a wireless network side and a wireless terminal side in order to control a communication traffic transfer path according to a situation as described above. Disclose. In this case, to allow uplink and downlink traffic for a traffic flow to go through the same radio bearer for one radio terminal, both the radio terminal and the corresponding mobility anchor in the radio network Need to be synchronized with respect to the current communication routing policy. Further, when the RAT to which the wireless terminal is connected is switched, the communication path control policy set on the wireless network side and the wireless terminal side must be changed in real time accordingly.

  Patent Document 1 describes a communication path of a traffic flow transmitted between a radio bearer terminal node and a radio terminal in a radio network on the premise of a PCC (Policy and Charging Control) architecture defined by the international standardization organization 3GPP. A mechanism for controlling based on a communication path control policy is disclosed. Specifically, the invention described in Patent Document 1 executes the following procedure. First, the wireless terminal transmits a communication path control policy by signaling to an application function implemented in the 3GPP core network. Subsequently, the application function analyzes the transmitted communication path control policy. Subsequently, the application function transmits the analysis result to the PCEF (policy control enforcement function) in the 3GPP core network by signaling. Finally, the PCEF in the 3GPP core network is positioned on the uplink transmission path and the downlink transmission path of the wireless terminal in order to reflect the communication control policy in the communication path control executed in the wireless network. An operation setting reflecting the communication control policy is performed on a relay node (router device or the like) in the 3GPP core network.

  Patent Document 2 discloses a technique in which a network reconfiguration unit on the network management apparatus side and a network reconfiguration unit on the communication terminal side cooperate to select a connection method on the communication terminal side based on a connection policy information table. . In Patent Document 2, the connection policy information table is stored in a network management apparatus installed in the network.

  The policy control described above signals communication within the core network by signaling a communication path control policy to each router device and each network device constituting the core network and optimizing the communication path from the core network to the wireless terminal. Optimize load distribution and relocation. Conventionally, the above-described policy control is designed mainly considering the optimization of the communication path in the core network, and each of the radio access network and the base station connected to the radio access network has a single RAT. It was implemented on the premise that only (radio access technology) is supported, that is, it does not have a multi-home function.

  On the other hand, multihomed base stations and wireless access points that do not apply the above-mentioned premise when implementing the policy control have recently been known. Multi-homed base stations and wireless access points support different RATs (Radio Access Technology), but it is possible to simultaneously provide multiple cells provided by the same base station in a superimposed manner to wireless terminals Base station. For example, femtocell base stations and the like that have become widespread in recent years can provide wireless terminals with both a communication cell for a cellular network and a communication coverage area for a wireless LAN. A plurality of cells provided in a superimposed manner by the same base station, although corresponding to different RATs (Radio Access Technologies) such as the communication cell for the cellular network and the communication coverage area of the wireless LAN described above, will be described below. It will be called a cooperation cell.

Special table 2012-512553 gazette JP 2009-246876 A

  As described above, the policy control described above is performed on the assumption that each of the radio access network and the base station connected thereto supports only a single RAT and does not have a multihome function. However, multi-homed base stations and the like have been installed and used on the wireless network side. In this case, the above-described policy control requires a mechanism for performing switching of wireless connection with a wireless terminal and traffic distribution control between a plurality of linked cells supported by the multihomed base station in a superimposed manner. . In addition, when implementing policy control, the status of switching between heterogeneous RATs and link aggregation and multi-home function on the base station side, which are executed on the wireless terminal side for switching communication and traffic distribution between radio bearers Depending on the situation, a specific mechanism for adaptively linking is required. However, the policy control described in Patent Document 1 and Patent Document 2 includes a mechanism for performing connection switching and traffic distribution between the linked cells described above, and a multi-home function on the base station side and connection switching between heterogeneous RATs on the wireless terminal side. It is not possible to realize a linkage mechanism with link aggregation.

  In addition, the policy control disclosed in Japanese Patent Laid-Open No. 2004-228688 is a method for controlling the uplink and downlink traffic of a wireless terminal within the wireless network that exists on the communication path of the wireless terminal when route control is performed within the wireless network. It is necessary to set a route control policy from the policy control node to the relay node (router device, etc.). In a wireless network managed by the same policy control node, if the number of connected wireless terminals and the frequency of policy control operations increase, the control overhead in the wireless network increases, which may hinder network operation. is there.

  In view of the above problems, the present invention provides a mechanism for executing connection switching and traffic distribution between linked cells described above when implementing policy control that adaptively controls communication paths in a wireless network according to the situation. It aims to be realized. Further, the present invention provides a multi-home function on the base station side and a connection switching between different RATs on the wireless terminal side and link aggregation when implementing policy control for adaptively controlling the communication path in the wireless network according to the situation. The purpose is to realize the mechanism of cooperation between the two. In addition, the present invention relates to the above-described path control, and in a wireless network managed by the same policy control node, even if the number of connected wireless terminals and the frequency of execution of policy control operations increase, The object is to realize policy control that does not increase overhead.

  As described above, according to the first aspect of the present invention, user traffic is communicated between a plurality of radio bearers while simultaneously and parallelly communicating between one or more base stations and a radio terminal via a plurality of radio bearers. A base station information received from a radio network and a list of cells to which the radio terminal is connected via the radio bearers; as a result of the comparison, When any one of the base stations supports two or more cells to which two or more of the radio bearers are connected in a superimposed manner, the base station supporting the execution of the process of allocating the optimum ratio and the Switching between wireless terminals; and the multi-homed base station or the wireless terminal switches the user traffic to a wireless base based on a policy set from the wireless network. Taking with the arrangement; determining a distribution for optimum distribution between La.

  Furthermore, in the first aspect of the present invention, the base station information includes a table that lists one or more cells that each of the one or more base stations supports in a superimposed manner, the one or more cells. Correspond to different RATs, and in the switching step, as a result of the comparison, all the cells listed in the base station information and all the cells included in the list of cells connected to the wireless terminal correspond one-to-one. If so, the step of switching the execution of the process of allocating the optimum ratio to the supporting base station is provided.

  In addition, according to a second aspect of the present invention, user traffic is transmitted on a radio bearer selected from a plurality of radio bearers that can be used simultaneously between one or more base stations and a radio terminal. A method comprising: comparing base station information received from a radio network with a list of base stations to which the radio terminal is connected via the plurality of radio bearers; as a result of the comparison, When any of the base stations supports two or more cells to which two or more of the base stations are connected in a superimposed manner, the base station supporting the execution of the process of selecting the radio bearer and the radio terminal And the supporting base station or the radio terminal selects a radio bearer from the plurality of radio bearers based on a policy set from the radio network, and selects the selected radio bearer. A configuration comprising; has been on the radio bearer transmitting said user traffic.

  Further, in the second aspect of the present invention, the base station information includes a table listing one or more cells that each of the one or more base stations supports in a superimposed manner, and the one or more cells Correspond to different RATs, and in the switching step, as a result of the comparison, all the cells listed in the base station information and all the cells included in the list of cells connected to the wireless terminal correspond one-to-one. If it does, it will comprise the step which switches execution of the process which selects the said radio bearer to the said base station to support.

  As described above, the present invention can realize a mechanism for performing connection switching and traffic distribution between the linked cells described above when implementing policy control for adaptively controlling communication paths in a wireless network according to the situation. it can. Further, the present invention provides a multi-home function on the base station side and a connection switching between different RATs on the wireless terminal side and link aggregation when implementing policy control for adaptively controlling the communication path in the wireless network according to the situation. The mechanism of cooperation with can be realized. In addition, the present invention relates to the above-described path control, and in a wireless network managed by the same policy control node, even if the number of connected wireless terminals and the frequency of execution of policy control operations increase, Policy control that does not increase the overhead can be realized.

The figure which shows the example of the base station which has a multihome function The figure which shows the structure of the radio | wireless communications system which concerns on this Embodiment. The figure which shows the apparatus structure of the radio | wireless terminal (UE) which a user uses in this Embodiment. The figure which shows the structure of the functional module group which implement | achieves this Embodiment The figure which shows the specific example of the base station information delivered to the radio | wireless terminal 10. Event flow diagram showing the flow of information between the functional modules shown in FIG. Flowchart illustrating a method for selecting a radio bearer used on a radio terminal The figure which illustrates one set of the candidate radio bearer which a radio | wireless terminal can use simultaneously.

  In the following description, first, a specific example of a multihomed base station used in a wireless network for implementation of the present embodiment will be described with reference to FIG. Next, a network configuration of the entire wireless communication system in which the present embodiment is realized and a hardware configuration of a wireless terminal used by a user in the wireless communication system will be described with reference to FIGS. Next, an outline of the policy control realized by the present embodiment on the premise of the network configuration shown in FIG. 2 and the wireless terminal device configuration shown in FIG. 3 will be described focusing on differences from the policy control in the prior art. To do. Next, a functional module configuration for realizing the policy control mechanism according to the present embodiment on the network configuration shown in FIG. 2 and the wireless terminal shown in FIG. 3 will be described with reference to FIG. Subsequently, referring to FIGS. 4 to 9, together with the flow of the policy control operation according to the present embodiment, under the policy control, the wireless terminal operates between linked cells on the base station side having the multihome function. A mechanism for switching communication between a plurality of radio bearers corresponding to different RATs in cooperation with the communication switching operation will be described.

<1> Specific example of multihomed base station used in this embodiment Hereinafter, with reference to FIGS. 1A and 1B, a specific example of a multihomed base station used in this embodiment. An example will be described. In FIG. 1A, the wireless terminal 10A is connected to the wireless communication carrier network 91 via the femtocell base station 90A, and the wireless terminal 10B is connected to the wireless communication carrier network via the macrocell base station 90B. 91 is connected. The wireless terminal 10 </ b> A and the wireless terminal 10 </ b> B can perform end-to-end communication with the Internet network 80 via the wireless communication carrier network 91. At the same time, each of the femtocell base station 90A and the macrocell base station 90B has a SIPTO (Selected IP Traffic Offload) connection that is a network connection for directly transferring traffic to the Internet network 80 without going through the wireless communication carrier network 91. The SIPTO connection is realized as follows, for example. An exemplary femtocell base station installed in an individual's home is a wireless carrier network via an ISP network provided by an ISP (Internet Service Provider) with whom the individual has contracted for connection to the Internet. As well as a direct connection to the Internet. Therefore, the femtocell base station transfers the voice call traffic transmitted and received by the wireless terminal with which it is communicating in the home to the wireless communication carrier network via the ISP network, and at the same time via the wireless communication carrier network. In addition, Internet communication traffic can be directly transferred to the Internet network (SIPTO).

  The femtocell base station 90A determines whether the traffic communicated with the radio terminal 10A is Internet communication traffic or voice call traffic. If it is Internet communication traffic, the femtocell base station 90A sends the traffic to the Internet via a SIPTO connection. Transfer directly to the network 80. As a result, the Internet communication traffic is offloaded from the wireless communication carrier network 91. Similarly, the macro cell base station 90B determines whether the traffic communicated with the wireless terminal 10B is Internet communication traffic or voice call traffic, and if it is Internet communication traffic, the traffic is transmitted via the SIPTO connection. Are directly transferred to the Internet network 80. As a result, the Internet communication traffic is offloaded from the wireless communication carrier network 91. The wireless carrier network 91 described above is also called a WSP (Wireless Service Provider) network, and can include a core network and a PDN behind the core network.

  In this way, the femtocell base station 90A is a base station that constitutes a cellular mobile phone network, but it does not go through the core network of a wireless communication carrier, but a broadband line (such as FTTH (Fiber-To-The-Home)). It has a network connection form that connects directly to the Internet via, for example. This connection form is a connection form generally called “SIPTO”. When the femtocell base station 90A provides such a network connection form to the Internet to a wireless terminal, the wireless interface for the wireless LAN specified in IEEE 802.11a / b / g / n or the like is used as an air interface or a carrier frequency. Other air interfaces and carrier frequencies can also be used. In this way, the femtocell base station 90A can provide both access to the cellular mobile phone network and wireless LAN access for Internet connection from a wireless terminal.

  As described above, the femtocell base station 90A can provide a wireless terminal with both a cellular network communication cell and a wireless LAN communication coverage area. A plurality of cells provided in a superimposed manner by the same base station, although corresponding to different RATs (Radio Access Technologies), such as the above-described cellular network communication cell and wireless LAN communication coverage area, are described below. Will be referred to as a linked cell. A multihomed base station or wireless access point is a base station or wireless access point that can simultaneously support a plurality of linked cells in a superimposed manner, like the femtocell base station 90A.

  The left side of FIG. 1B shows a state in which the femtocell base station 90A provides a wireless terminal with both a cellular network communication cell and a wireless LAN communication coverage area. In this state, the femtocell base station 90A provides a radio network access service to the radio terminal 10 by simultaneously using both the radio bearer connected to the cellular network and the radio bearer connected to the wireless LAN in parallel. It is possible. That is, when the base station is multi-homed, a plurality of linked cells (and corresponding radio bearers) corresponding to different RATs are provided in parallel to the radio terminal from the same base station, Parallel wireless transmission to the same base station is possible using these multiple linked cells. In this case, it is possible to turn off the heterogeneous RAT connection switching and link aggregation in the wireless terminal 10 and execute functions corresponding to the heterogeneous RAT connection switching and link aggregation in the femtocell base station 90A. . That is, the function of switching a plurality of radio bearers corresponding to different RATs for radio transmission, and controlling the distribution of user traffic among the plurality of radio bearers is performed by the femtocell instead of being executed on the radio terminal 10 side. It can be executed in the base station 90A.

  On the other hand, the right side of FIG. 1B shows a state where the wireless terminal 10 is served by both the cellular base station 90C and the wireless LAN access point 90D that do not have the multihome function. In this state, the cellular base station 90C provides only the communication cell and the radio bearer connected to the cellular network to the radio terminal 10, and the radio LAN access point 90D is provided only for the communication coverage area and the radio bearer connected to the radio LAN. Is provided to the wireless terminal 10. Further, in this state, the wireless terminal 10 is located in an intersection area between the communication cell provided by the cellular base station 90C and the communication coverage area provided by the wireless LAN access point 90D. In this case, the switching of connection between different RATs and the execution of link aggregation in the radio terminal 10 are turned on, a plurality of radio bearers corresponding to different RATs are switched, and user traffic is distributed and controlled between these radio bearers. The function to be performed must be executed on the wireless terminal 10 side.

<2> Network Configuration of Radio Communication System According to this Embodiment Hereinafter, the network configuration of the radio communication system according to this embodiment will be described using FIG. 2 includes one or more core networks (CN) connected to the UE 10, one or more radio access networks 40A to 40C, and the radio access networks 40A to 40C via core network gateways 61 to 62. Network) 51/52, the Internet network 80 connected to the core network 51/52 via the PDN gateway 71/72, and the server 20 connected to the Internet network 80.

  The radio access networks 40A to 40C are networks that provide the UE 10 with a radio access path to the core network via radio communication, and each of the radio access networks 40A to 40C can be based on different RATs. is there. For example, the radio access network 40A can be an LTE network based on the E-UTRAN standard that 3GPP is standardizing, and the radio access network 40B can be a WiMAX network based on the IEEE 802.16e standard. The access network 40C can be a wireless LAN network such as Wi-Fi. The wireless access network 40C can be composed of one or more wireless LAN access points and an Ethernet hub, a broadband router, a cable modem, and the like that connect them.

  The core networks 51 and 52 are formed by connecting a number of router devices and network control server devices through high-speed lines within a wireless communication service provider, and connecting the UE to the Internet (in the E-UTRAN core network) Corresponds to a P-GW (PDN-Gateway) function), UE terminal mobility management (corresponding to the MME function in the E-UTRAN core network) or UE communication service authentication (E-UTRAN core network) , Which corresponds to the HSS function). For example, the core network 51 can be wirelessly accessed from the UE 10 via the wireless access network 40A and the core network gateway 61. On the other hand, the core network 52 is wirelessly accessible from the UE 10 via the wireless access network 40B and the core network gateway 62. Although not shown in FIG. 2, it is also possible to wirelessly access the same core network via two or more different wireless access networks.

  The ISP network 53 includes an FTTH (Fiber-To-The-Home) line, a DSL (Digital Subscriber Line) line, and a LAN wide area network for connecting the wireless LAN network 40C to a router network (PDN: Packet Data Network) 54. It can be a wide area Ethernet or the like.

  The PDN gateway 71/72 connects the core network 51/52 to a router network (PDN: Packet Data Network) 54, whereby the core network 51/52 passes through the router network (PDN: Packet Data Network) 54. Thus, traffic can be communicated with the Internet network 80. When the core network 51 is configured based on the E-UTRAN standard, the PDN gateway 71 can be a P-GW (PDN-Gateway).

  A router network (PDN: Packet Data Network) 54 is a packet exchange type network that is interposed between the core network 51/52 and the Internet network 80 and between the ISP network 53 and the Internet network 80. It also provides transfer control of roaming traffic between networks. The router network 54 is depicted as a single network connecting the plurality of core networks 51/52 to the Internet network 80 in the network configuration of FIG. It is good also as a structure which exists in. Further, the core network 51 and the core network 52 may be connected to the Internet network 80 via different router networks 54.

  In the network configuration shown in FIG. 2, a policy control server that manages policy control operations for communications within a wireless network is installed in the core network 51/52, in a router network (PDN: Packet Data Network) 54, or in the Internet network 80. It is possible. When the core network 51/52 is configured in accordance with the provisions of 3GPP Release 7, the policy control server can be implemented as a part of the function of the P-GW (PDN-Gateway) in the core network 51/52. is there. In this case, the P-GW (PDN-Gateway) may be the external connection gateway 71 installed in the core network 51 of FIG. The policy control server according to the present embodiment executes policy control that is not limited to a specific core network or a specific radio access network. Therefore, even when the policy control server is installed in the core network 51, for example, the policy control server performs policy control with the network device in another core network via the Internet network 80. It is possible to perform communication regarding. When the policy control server is installed in the Internet network 80, the policy control server is compatible with the TCP / IP protocol layer structure for communicating policy information with the core network 51/52. A COPS (Common Open Policy Service) protocol may be used. In addition, the policy control server installed in the core network 51 is compatible with the TCP / IP protocol layer structure in order to communicate policy information with the network devices in the other core network 52 via the Internet network 80. A COPS (Common Open Policy Service) protocol may be used.

  In FIG. 2, a radio bearer 30A is radio connection means for connecting the UE 10 to a radio access network 40A that is an LTE network. Similarly, the radio bearer 30B is a radio connection unit that connects the UE 10 to a radio access network 40B that is a WiMAX network. The radio bearer 30C is a radio connection unit that connects the UE 10 to a radio access network 40C that is a Wi-Fi network.

  In FIG. 2, the UE 10 wirelessly connects to any one or more of the radio access networks 40A to 40C using any one or more of the radio bearers 30A to 30C. Subsequently, the UE 10 performs end-to-end communication based on TCP / IP with the server 20 via the radio access network, the core network 51/52, and the Internet network 80.

<3> Hardware configuration of UE used in the present embodiment Hereinafter, a hardware configuration of UE 10 used in the radio communication system according to the present embodiment will be described with reference to FIG.

  In FIG. 3, the UE communicates with the user while exchanging input / output data with the antenna 101 for transmitting and receiving radio signals, the radio interfaces 102a to 102n connected to the antenna 101, the memory 103, the control processor 104, and the control processor 104. A user input / output device 105 that controls a user interface with the UE 10, a storage 106 that is a permanent storage medium that stores setting parameters of the UE 10, and a bus 107 are configured. The memory 103, the control processor 104, the user input / output device 105, and the storage 106 described above are connected to each other via a bus 107.

  Each of the wireless interfaces 102a to 102n converts the received RF signal by frequency down-converting, digitizing, demodulating, and decoding, thereby converting it into digital information and providing it for subsequent information processing. In contrast, each of the radio interfaces 102a-102n converts the digital information generated in the UE 10 into an RF signal by encoding, modulating, and frequency up-converting it into an antenna for radio transmission. 101. Each of the wireless interfaces 102a to 102n is configured to be able to execute signal processing corresponding to a plurality of different types of RAT such as LTE, WiMAX, or wireless LAN. That is, each of the wireless interfaces 102a to 102n has a one-to-one correspondence with each of the n types of RATs. For example, the wireless interface 102a is configured to execute wireless signal transmission / reception processing compatible with the LTE network, the wireless interface 102b is configured to execute wireless signal transmission / reception processing compatible with the WiMAX network, and the wireless interface 102c includes The wireless signal transmission / reception process corresponding to the wireless LAN network can be executed.

  The memory 103 stores digital information exchanged between the wireless interfaces 102a to 102n and a control processor 104 described later, a program for controlling the entire UE 10, and the like.

  The control processor 104 reads the program from the memory 103, controls the entire UE 10, generates digital information transmitted from the antenna 101 via the radio interfaces 102a to 102n, and receives the digital information received from the antenna 101 via the radio interfaces 102a to 102n. Perform further processing of information.

  The control processor 104 selectively enables any one or more of the wireless interfaces 102a to 102n, and exchanges digital information via only the enabled wireless interface via the bus 107, thereby specifying a specific one. Communication can be performed selectively using the RAT. In addition, the control processor 104 enables all of the wireless interfaces 102a to 102n, and exchanges digital information via all the wireless interfaces 102a to 102n via the bus 107, so that all the RATs (wireless) that can be used simultaneously are transmitted. Access network) can be used simultaneously for communication.

  The user input / output device 105 exchanges input / output data between the screen display and keypad provided on the UE 10 and the control processor 104, and at the same time controls the user interface between the user and the UE 10. . In addition, when the device state or input / output status of the screen display or keypad provided on the UE 10 changes, the user input / output device 105 performs interrupt processing related to the change via the bus 107. Instructs the control processor 104. In order to enable such interrupt control, the user input / output device 105 has a function of electrically monitoring input / output device states such as a screen display and a keypad managed by the user input / output device 105.

<4> Outline of Policy Control of Communication Path in Wireless Communication System (4-1) General Explanation of Policy Control in Wireless Network Policy in policy control is roughly divided into two types: operation policy and device setting policy. The The operation policy describes the network operation guidelines set by the network operation manager of the wireless network, and describes the function and quality of the communication service required by the communication application for each communication application executed on the wireless network. Things. The operation policy may describe a function that the user wants to select from among the communication control functions of the wireless terminal. On the other hand, the device setting policy is generated from the result of analysis of the operation policy by the policy control entity in order to reflect the operation policy on the operation of each network device in the wireless network. This is a policy set for network devices.

  When a communication path control based on a policy is performed for a traffic flow communicated via a wireless network by a wireless terminal, each policy control operation is divided into a determination stage and an enforcement stage. The determination stage is started by a request from the wireless terminal side or the wireless network side. Based on the traffic flow description information received from the wireless terminal side or the wireless network side and the operation information of the network device in the wireless network, Determine the specific content of the policy to be applied to the flow. In the enforcement stage, the specific contents of the policy determined in the judgment stage are set in one or more network devices in the wireless terminal or the wireless network, and the traffic flow is transferred according to the set policy. Instructs the wireless terminal or the network device.

  In order to implement the policy control operation described above in the wireless network, (1) on the network device subject to policy control, the traffic flow is transferred according to the policy contents set by the device setting policy received from the outside. (2) In the wireless network, determine the device setting policy that should be set for the network device subject to policy control according to the analysis result and status of the operation policy, It is necessary to implement a policy control mechanism for setting the determined device setting policy for the network device. According to the rules of 3GPP Release 7, it should be set for the network devices (core network gateways 61 to 63 in FIG. 2) subject to policy control in the 3GPP core network (such as the core network 51 in FIG. 2). The entity that determines the device setting policy according to the operation policy and the situation is the PCRF (policy and charging rule function), and the entity that sets the determined device setting policy for the network device is PCEF (policy and charging enforcement) Function). The PCRF and PCEF can be realized as a function of a policy control server (such as the external connection gateway 71/72 in FIG. 2) that implements a policy control mechanism in the core network (such as the core network 51 in FIG. 2).

(4-2) This embodiment is different from communication path policy control in the prior art. With the PCC architecture, which is a policy control framework in the 3GPP core network, as an implementation base, the traffic flow that wireless terminals communicate with The policy control described in Patent Document 1 executed for communication path control is different from the present embodiment in the following two points.
(A) First Difference In the present embodiment, it is the wireless terminal (shown in FIGS. 2 and 3) that adjusts the operation of the communication path control according to the device setting policy set by the policy control mechanism in the wireless network. UE 10) and only base stations with multi-home function. On the other hand, in the conventional communication path policy control including Patent Document 1, the device for which the operation of the communication path control is adjusted according to the device setting policy set by the policy control mechanism in the wireless network is a wireless terminal, All router devices and network devices (core network gateways 61 to 63, etc. in FIG. 2) in a wireless network (such as the core network 51 / core network 52 in FIG. 2) located on the communication path of the wireless terminal as well as the base station. ) Is also included. For example, each router device located on the communication path of a wireless terminal routes traffic flows communicated by the same wireless terminal to different output side network interfaces by setting different device setting policies from the policy control mechanism. There is a case.
(B) Second difference In the present embodiment, the control of the communication path based on the policy control framework is the switching or simultaneous use of a plurality of radio bearers for connecting wireless terminals to different RATs. The communication path control is not related to the communication path control in the core network (such as the core network 51 in FIG. 2) ahead of the radio access network. In addition, in the present embodiment, switching between a plurality of radio bearers and simultaneous setting change operation are not unilaterally instructed from the policy control mechanism on the radio network side, and the radio terminal performs the policy control. It is executed under the initiative of the wireless terminal while referring to the policy received from the mechanism. Therefore, in the present embodiment, the current policy setting state related to communication path control only needs to be managed on the wireless terminal, and therefore the policy control according to the present embodiment is terminal-driven communication path policy control. I can say that.

  On the other hand, in the conventional communication path policy control including Patent Document 1, all router devices and network devices in the core network (such as the core network 51 in FIG. 2) located on the communication path of the wireless terminal (see FIG. 2). 2 core network gateways 61-63, etc.) are controlled. In this case, the setting change of the routing operation for the router device and the network device (such as the core network gateways 61 to 63 in FIG. 2) is unilaterally instructed from the policy control mechanism on the wireless network side, The router device and the network device (such as the core network gateways 61 to 63 in FIG. 2) are not determined autonomously. In such conventional communication path policy control, the communication path itself in the core network (such as the core network 51 in FIG. 2) is directly controlled by policy control executed on the traffic flow communicated by the wireless terminal. Controlled. As a result, when the communication path in the core network is changed by the policy control, the change is transferred to the mobility anchor (in the 3GPP core network, the MME in the core network (such as the core network 51 in FIG. 2)) corresponding to the wireless terminal. Or implemented as a PDN-GW) or a radio bearer termination node (implemented as a GGSN in the 3GPP core network). Therefore, the radio terminal must synchronize with respect to the policy setting change with the mobility anchor or the radio bearer end node. In other words, it can be said that the conventional communication path policy control including Patent Document 1 is network-driven policy control that needs to manage policy setting changes while synchronizing the entire core network.

<5> Functional Module Configuration for Implementing Policy Control Function According to this Embodiment Hereinafter, referring to FIG. 4, the network configuration shown in FIG. 2 and the wireless terminal shown in FIG. A functional module configuration for realizing the policy control mechanism will be described.

(5-1) Overview of Overall Configuration In FIG. 4, the policy control mechanism 200 corresponding to the policy control mechanism on the wireless network side described in (ii) above includes an external bearer setting unit 210, an external information acquisition unit 220, and an operation The system (network operation management system) 230 includes three functional modules. The external bearer setting unit 210 and the external information acquisition unit 220 are realized by a policy control server installed in the wireless network executing dedicated server software. The policy control mechanism 200 shown in FIG. 4 provides a common policy control mechanism that is not limited to a specific radio core network or a specific radio access network to all radio networks that can be used from the radio terminal (UE) 10. . Therefore, it is preferable that the policy control server that implements the policy control mechanism 200 is installed in a router network (PDN (Packet Data Network)) 54 that is independent of the Internet network 80 or a specific wireless core network. When the policy control server is installed in a specific core network, the policy control server exchanges policy information with a policy setting target device in another core network using a COPS protocol or the like. In addition, when there are two or more router networks 54 for each wireless communication provider and a policy control server is installed in any one of the router networks 54, the COPS protocol or the like is used for all the router networks 54. It is also possible to collect the network information in the router network 54 in which the policy control server is installed. As a result, even in such a multi-router network configuration, the policy control mechanism 200 shown in FIG. 4 can be provided as a common policy control mechanism that is not limited to a specific wireless core network or a specific wireless access network. .

As shown in FIG. 4, the policy control mechanism 200 is connected to a radio terminal (UE) 10 via a radio bearer 1, a radio bearer 2,..., A radio bearer N, and is connected via radio bearers 1 to N. Each of the N radio communication paths passes through N different radio access networks (first RAT to Nth RAT) and is one of one or more radio core networks behind the radio access networks. Via. When the policy control mechanism 200 sets a device setting policy associated with a specific radio bearer in the radio terminal (UE) 10, the device setting policy is distributed via the specific radio bearer. In FIG. 4, the radio access networks to which the radio bearers 1 to N are connected are shown as radio networks 300 ₁ to 300 _{n in} a form in which the radio access networks connected to the radio bearers 1 to N are combined with the radio core network behind them.

(5-2) Functional Module Configuration of Policy Control Mechanism 200 on Radio Network Side Next, a functional module configuration of the policy control mechanism 200 will be described as follows.

  The external bearer setting unit 210 sets a predetermined device setting policy for the radio terminal in order to control the operation of the radio terminal (UE) 10 selecting a plurality of radio bearers connected to different RATs based on the policy. To do. At this time, the setting of the device setting policy for the wireless terminal is achieved as follows. First, the policy control server transmits the contents of a device setting policy to be set using a policy transmission protocol such as a COPS protocol to the wireless terminal. Subsequently, the policy enforcement mechanism in the wireless terminal changes the setting of its own operation control parameter according to the contents of the transmitted device setting policy.

  The external bearer setting unit 210 includes an acquired information analysis unit 211 and a policy distribution unit 212. The acquired information analysis unit 211 analyzes the operation policy manually set by the network operation manager of the wireless network and the net arc device information collected from a large number of network devices constituting the wireless network to analyze each wireless terminal (UE) 10. Determine the contents of the device setting policy that should be set to. In addition, the acquired information analysis unit 211 analyzes base station information collected from a large number of network devices constituting the wireless network, and determines base station information to be transmitted to each wireless terminal (UE) 10. The role played by the base station information and its specific configuration will be described later. The policy distribution unit 212 is connected to the radio terminal (UE) 10 via any one or more of the radio bearers 1 to N. The policy distribution unit 212 sets the determined device setting policy to the wireless terminal (UE) 10 in order to set the device setting policy determined by the acquired information analysis unit 211 to the wireless terminal that is the target of policy control. Distribution is performed via any one or more of bearer 1 to radio bearer N. At the same time, the policy distribution unit 212 transmits the base station information to one of the radio bearers 1 to N in order to transmit the base station information determined by the acquired information analysis unit 211 to the radio terminal (UE) 10. Deliver through more than one.

The external information acquisition unit 220 includes a network information acquisition unit 221 and an operator / policy acquisition unit 222. The network information acquisition unit 221 collects network device information related to the current operating state of the device and the current communication capability from each network device in the wireless network. For example, the network information acquisition unit 221 includes, from router devices and network devices constituting the wireless networks 300 ₁ to 300 _n to which the wireless bearers 1 to N are connected, the configuration, function, operating status, and communication of the devices. Collect network device information related to performance. The operator / policy acquisition unit 222 acquires an operation policy manually set by a network operation manager of the wireless network. The external information acquisition unit 220 transmits the network device information and the operation policy acquired by the network information acquisition unit 221 and the operator / policy acquisition unit 222 to the acquisition information analysis unit 211, respectively.

The operation system 230 is provided for each wireless communication carrier network, and there are as many operation systems 230 as the number of wireless communication carrier networks (230A to 230N in FIG. 4). The operation system 230 for each wireless communication carrier network is “network device information” that is information describing the configuration and functions of the network devices from all the network devices in the wireless communication carrier network under its management. Are collected and reported to the network information acquisition unit 221 in the external information acquisition unit 220. In one embodiment, the n wireless communication operator networks may correspond to the wireless networks 300 _{1 to} 300 _n in FIG. In this case, the configuration of all network devices constituting the wireless network 300 _1, function, network equipment information describing the operating condition and communication performance is collected by the operations system 230A in FIG. 4, in the wireless network 300 ₂ network device information of all network equipment is collected by the operation system 230B in FIG. 4, ..., the network device information of the wireless network 300 _n are collected by the operations system 230N in FIG. Each operation system 230 can be realized by a network operation management server installed in each wireless communication carrier network. In one embodiment, the network operation management server accesses the MIB (Module Information Base) of each network device constituting the wireless communication carrier network by using the SNMP protocol, so that the configuration, function, and operation of each network device are performed. It is possible to collect network device information that describes the situation and communication performance. Network device information about all network devices in the wireless networks 300 _{1 to} 300 _n collected by the operation systems 230A to 230N is collected by the network information acquisition unit 221 in the external information acquisition unit 220.

(5-3) Functional Module Configuration on Radio Terminal (UE) 10 Side Next, a functional module configuration on the radio terminal (UE) 10 side in FIG. 4 will be described. This functional module configuration refers to the above-described (for controlling switching and simultaneous parallel access of a plurality of radio bearers respectively connected to different RATs on the radio terminal (UE) 10 while referring to a policy supplied from the radio network side. This corresponds to the mechanism of i). The functional module configuration on the radio terminal (UE) 10 side includes two functional modules, an internal bearer setting unit 110 and an internal information acquisition unit 120. The above-described functional modules on the radio terminal (UE) 10 side are realized by the control processor 104 in the radio terminal (UE) 10 executing a dedicated software program read from the storage 106 onto the memory 103.

  The internal bearer setting unit 110 includes one or more radio bearers used by the radio terminal (UE) 10 to connect to the radio network from the radio bearers 1 to N that can be simultaneously used by the radio terminal (UE) 10. The function to select is executed. At this time, when two or more radio bearers are selected by the internal bearer setting unit 110 in order for the radio terminal (UE) 10 to connect to the radio network, the internal bearer setting unit 110 further includes the two or more radio bearers. The operation of optimally allocating the traffic amount to be communicated on the two or more radio bearers between the two or more radio bearers is executed. At this time, the selection of the radio bearer executed by the internal bearer setting unit 110 as described above and the optimum traffic distribution among the selected radio bearers are determined by the device setting policy set in the radio terminal 10 from the policy distribution unit 212. Performed according to the criteria described. In the following description, the operation of selecting radio bearers performed by the internal bearer setting unit 110 as described above and the operation of optimal traffic distribution among the selected radio bearers are simply referred to as bearer selection operations.

  The internal bearer setting unit 110 first receives the base station information and the device setting policy distributed from the policy distribution unit 212. Subsequently, the internal bearer setting unit 110 should execute a bearer selection operation in the radio terminal (UE) 10 based on the base station information or on the base station side to which the radio terminal (UE) 10 is connected. Decide what should be. That is, based on the base station information, the internal bearer setting unit 110 executes a determination for switching the execution subject of the bearer selection operation between the radio terminal (UE) 10 and the base station to which the bearer selection operation is connected. When it is determined that the execution subject of the bearer selection operation should be switched to the radio terminal (UE) 10, the internal bearer setting unit 110 uses the radio terminal 10 for communication from among the radio bearers 1 to N that can be used simultaneously. Either the switching unit 111 or the simultaneous communication processing unit 112 is caused to execute an operation of selecting a radio bearer. Therefore, the internal bearer setting unit 110 selects radio bearers to be used for traffic transmission from radio bearers that can be used simultaneously, and sets the device setting policy as a reference for performing traffic distribution control between the radio bearers. This is transmitted to one of the simultaneous communication processing units 112. In the internal bearer setting unit 110, which of the switching unit 111 and the simultaneous communication processing unit 112 should execute the operation of selecting a radio bearer is determined by the activation unit 113 as described later. However, as will be described later, the execution subject of the bearer selection operation may be switched from the radio terminal (UE) 10 to the side of the base station in communication therewith. Therefore, the policy distribution unit 212 must distribute the base station information and the device setting policy necessary for controlling the bearer selection operation to the base station.

  The internal bearer setting unit 110 includes a switching unit 111, a simultaneous communication processing unit 112, and an activation unit 113.

  The switching unit 111 first selects a radio bearer based on the device setting policy set in the radio terminal (UE) 10 from the policy distribution unit 212. Subsequently, the switching unit 111 transmits an uplink signal via the selected radio bearer. Note that the switching unit 111 performs the same control as described above even when a downlink signal is received from the radio network side via one or more of the radio bearers 1 to N. In this case, the radio bearer selected by the switching unit 111 may be different between the downlink and uplink cases. The simultaneous communication processing unit 112 first assigns the number of bits of an information signal that can be transmitted for each radio bearer based on the device setting policy set in the radio terminal (UE) 10 from the policy distribution unit 212. Subsequently, the simultaneous communication processing unit 112 transmits an uplink signal by the number of bits allocated to each radio bearer via each radio bearer. Note that the simultaneous communication processing unit 112 performs the same control as described above even when a downlink signal is received from the radio network side via one or more of the radio bearers 1 to N. At this time, regarding the radio bearer that is not selected for transmission / reception of the uplink signal or the downlink signal among the radio bearers 1 to N, the simultaneous communication processing unit 112 sets 0 as the number of bits of the information signal that can be transmitted. By assigning bits, the radio bearer can be excluded from selection targets. As described above, the simultaneous communication processing unit 112 optimizes uplink and downlink traffic distribution among a plurality of radio bearers according to a policy set from the radio network side. In consideration of policies set from the wireless network side, when the simultaneous communication processing unit 112 optimizes traffic distribution among a plurality of radio bearers, traffic allocation is performed so that traffic allocation differs between uplink and downlink. May be determined.

  The activating unit 113 instructs the switching unit 111 to start executing a function of selecting a single radio bearer to be used for communication from the radio bearers 1 to N. Alternatively, the activating unit 113 indicates to the simultaneous communication processing unit 112 the timing to start execution of the optimal distribution of traffic among one or more radio bearers used for communication from among the radio bearers 1 to N. Instruct. Further, the activating unit 113 determines whether the switching unit 111 or the simultaneous communication processing unit 112 is to perform an operation of selecting a radio bearer used for communication by the radio terminal (UE) 10. The deciding operation may be executed by the activating unit 113 according to the device setting policy set by the user in the radio terminal (UE) 10.

  The activating unit 113 is activated by the internal bearer setting unit 110 when the internal bearer setting unit 110 determines that the execution subject of the bearer selection operation should be switched to the wireless terminal 10 side, and the activation unit 113 activates the switching unit 111 or the simultaneous communication processing unit 112. On the other hand, the above operation is executed. The internal bearer setting unit 110 can periodically perform an operation of determining whether or not to switch the execution subject of the bearer selection operation to the wireless terminal 10 side at regular time intervals. Further, as another embodiment, the internal bearer setting unit 110 detects the occurrence of a predetermined event event generated by software or hardware in the radio terminal (UE) 10, and according to the occurrence of the event event, It is possible to determine whether or not the execution subject of the bearer selection operation should be switched to the wireless terminal 10 side.

  The internal information acquisition unit 120 measures the communication performance, communication settings, communication state, and the like inside the wireless terminal 10, stores the measurement results therein as internal information, and stores the stored internal information. This is transmitted to the internal bearer setting unit 110 in response to a request from the internal bearer setting unit 110. The operation in which the internal information acquisition unit 120 measures the communication performance, communication settings, communication state, and the like inside the wireless terminal (UE) 10 can be realized as follows. For example, in the radio terminal (UE) 10, the control processor 104 (FIG. 3) executing the internal information acquisition unit 120 is for communication operation monitoring provided by an operating system resident on the memory 103 (FIG. 3). The above-described measurement can be performed by calling and executing the API. The internal information transmitted from the internal information acquisition unit 120 to the internal bearer setting unit 110 is used to set the device setting policy distributed from the policy distribution unit 212 by the internal bearer setting unit 110 to the communication performance and communication within the radio terminal (UE) 10. It is used to correct the settings and communication status. Details regarding this point will be described later.

<6> Flow of Policy Control Operation Hereinafter, with reference to FIG. 4 to FIG. 9, the functional modules on the wireless network side and the wireless terminal (UE) side shown in FIG. The flow of the operation when doing this will be described.

(6-1) Flow of Operation on Policy Control Mechanism 200 Side FIG. 5 referred to for the following explanation is a diagram showing a specific example of base station information distributed from the policy control mechanism 200 to the radio terminal (UE) 10. FIG. 6 is an event flow diagram showing a flow of information between the function modules on the radio network side and the radio terminal (UE) side shown in FIG.

First, the policy distribution unit 212 in the external bearer setting unit 210 first transmits the device setting policy generated for setting to the radio terminal (UE) 10 via one of the radio bearer 1 to the radio bearer N. 10 (step S1000 in FIG. 6). The role and information content of the device setting policy distributed to the radio terminal (UE) 10 at this time will be described later. Subsequently, each of the operation systems 230A to 230N collects information describing the configurations and functions of all the network devices in the wireless network under its management (step S1001 in FIG. 6). For example, operating system 230A collects network device information of all the network devices constituting the wireless network 300 _1, operating system 230B may collect network device information of all the network devices constituting the wireless network 300 ₂ and, ..., operating system 230N collects network device information of the wireless network 300 _n. Subsequently, the network information acquisition unit 221 in the external information acquisition unit 220 collects network device information of all router devices and network devices in the wireless networks 300 _{1 to} 300 _n from the operation systems 230A to 230N (FIG. 6). Steps S1002 and S1003). Wireless network 300 ₁ in FIG. 4, which illustrates integrally wireless core network and router network in a cellular radio network and behind, such as the LTE network, the wireless network 300 _n in FIG. 4, a wireless LAN that A wireless core network and a router network behind are integrally illustrated.

  Subsequently, the network information acquisition unit 221 transmits the network device information acquired from the operation system 230 to the acquisition information analysis unit 211 in the external bearer setting unit 210 (step S1004 in FIG. 6).

  In parallel with this, when a network operation administrator manually inputs a wireless network operation policy, the operator policy acquisition unit 222 transmits the input operation policy to the acquisition information analysis unit 211.

Subsequently, the acquired information analysis unit 211 generates base station information from network device information collected from network devices located on the communication path of each radio bearer in the radio networks 300 _{1 to} 300 _n . The base station information is information that lists, for each base station, linked cells that each base station simultaneously supports in a superimposed manner. All the multihomed base stations connected to the wireless networks 300 _{1 to} 300 _n and multi Generated for home wireless access points and combined into a single tabular format. When base station information is generated for all base stations and wireless access points existing in the wireless networks 300 _{1 to} 300 _n , the amount of information of the base station information becomes enormous. Therefore, the acquired information analysis unit 211 can generate base station information only for base stations and wireless access points that are within a predetermined range centering on the geographical position where the wireless terminal (UE) 10 is located. Thereby, base station information is generated only for base stations or wireless access points to which the wireless terminal (UE) 10 may connect in the near future. A specific example of the base station information is shown in FIG.

  Hereinafter, the base station information illustrated in FIG. 5 will be described on the premise of the network configuration shown in FIG. In the table shown in FIG. 5 as a specific example of the base station information, each row indicated by item number = 1, 2, 3,... Is superimposed on each of the base station and the wireless access point having the multihome function. The cell identifiers (cell IDs) of all supported cooperative cells are listed. Here, when one or more of the linked cells is a wireless LAN, the cell coverage defined by the cellular radio network is not used to identify the linked cell, but communication coverage is provided to the linked cell. The MAC address of the wireless LAN access point to be provided must be used. Therefore, in the following description, as an identifier for identifying a linked cell, both a MAC address for identifying a wireless LAN communication area and a cell ID for identifying a cell in a cellular radio network are collectively referred to as a cell ID. For example, a multi-homed base station corresponding to the row of item number = 1 supports the following three cells as linked cells corresponding to different types of RATs. These include an LTE cell (primary cell) with a cell ID = 100 as a cell identifier, a 2 Gbps WiFi communication area with a cell ID = 200 as the MAC address of the access point, and a cell ID = 300 as the MAC address of the access point. 3 cells in a 5 Gbps WiFi communication area. Similarly, the multihomed base station corresponding to the row with the item number = 2 supports the following four cells in a superimposed manner as linked cells corresponding to the heterogeneous RAT. These include an LTE cell (primary cell) with cell ID = 110 as the cell identifier, a 2 Gbps WiFi communication area with cell ID = 210 as the MAC address of the access point, and cell ID = 310 as the MAC address of the access point. It is a WiFi communication area of 5 Gbps, and four cells of a WiMAX base station having a cell ID = 410 as a cell identifier.

This base station information is distributed from each of the operation systems 230A to 230N to the wireless terminal 10 via each base station connected to each of the wireless networks 300 _{1 to} 300 _n managed by each operation system. As a result, when the radio terminal (UE) 10 is handed over between base stations, the radio terminal 10 can know whether the handover source base station and the handover destination base station each have a multihome function. . In addition, at the time of handover between base stations, the radio terminal (UE) 10 displays a list of all linked cells that are simultaneously supported in a superimposed manner by these base stations having a multihome function and a list of RAT types corresponding to each linked cell. Can be acquired.

Subsequently, the acquisition information analysis unit 211 in the external bearer setting unit 210 is based on the network device information of the network device in the wireless network acquired from the network information acquisition unit 221 and the operation policy acquired from the operator / policy acquisition unit 222. The device setting policy to be set in the radio terminal (UE) 10 for each radio bearer (each of radio bearer 1 to radio bearer N) is determined. Hereinafter, the specific content of the apparatus setting policy set to the radio | wireless terminal (UE) 10 from the external bearer setting part 210 is demonstrated. The device setting policy is that radio communication is performed for all RATs that may be simultaneously connected from the radio terminal 10 via the radio bearers 1 to N among the RATs corresponding to the radio networks 300 _{1 to} 300 _n. The weighting factor applied on the terminal (UE) 10 is included. That is, this weighting coefficient is used when the radio terminal (UE) 10 allocates uplink and downlink traffic volume between radio bearers, and traffic for each radio bearer according to the RAT type to which each radio bearer corresponds. This is a coefficient for weighting the distribution amount.

The acquired information analysis unit 211 can determine the weighting coefficient included in the device setting policy to be set in the radio terminal (UE) 10 for each of all base stations to which the radio terminal 10 may connect. . The acquisition information analysis unit 211 can determine the weighting coefficient for each base station, for example, as in the following (S1) to (S4).
(S1) The acquisition information analysis unit 211 first analyzes network device information collected from each of the wireless networks 300 _{1 to} 300 _n corresponding to one or more wireless communication carrier networks. The collected network device information (for example, MIB information defined by the network operation management protocol SNMP) indicates the configuration, function, operating status, and communication performance of the router devices and network devices that constitute each of the wireless networks 300 _{1 to} 300 _n. Represent.
(S2) Subsequently, the acquired information analysis unit 211 determines, based on the result of the analysis, end-to-end between the radio access network, core network or router network constituting each of the radio networks 300 _{1 to} 300 _n and each base station. Deriving the connection relationship on the end communication path. For example, the acquired information analysis unit 211 extracts the connection topology between router devices in the wireless networks 300 _{1 to} 300 _n and the tracking information of packets flowing through the end-to-end communication path from the analysis result of (S1). can do. Then, the acquired information analysis unit 211 determines the end-to-end communication path between each base station and the radio access network, core network or router network that constitutes the radio networks 300 _{1 to} 300 _n based on these extraction results. It is possible to derive the connection relationship above.
(S3) Subsequently, the acquired information analysis unit 211 determines that the wireless access network, core network, or router on the end-to-end communication path passing through each base station based on the analysis results of (S1) and (S2). Estimate communication load etc. for the network. Specifically, the ratio of the current packet transfer rate and the maximum packet transfer rate of the router devices and network devices that make up each network is calculated, the ratio is averaged over the entire network, and this average value is calculated for the entire network. It can be used as an index of communication load.
(S4) Based on the result of (S3) above, the acquired information analysis unit 211 determines the communication load of the radio access network, the core network, or the router network for each RAT corresponding to each of the radio networks 300 _{1 to} 300 _n. Can be evaluated. Subsequently, the acquired information analysis unit 211 has a high communication load or a high communication load for each radio access network, core network, or router network for each end-to-end communication path passing through each base station. For example, the corresponding RAT weighting coefficient is set large. Conversely, the acquired information analysis unit 211 tends to have a low communication load or a low communication load for each radio access network, core network, or router network for each end-to-end communication path passing through each base station. If there is, the corresponding RAT weighting coefficient is set small. In addition, when the acquired information analysis unit 211 determines the above-described weighting coefficient for each RAT, it may be determined in consideration of the operation policy acquired from the operator / policy acquisition unit 222.

In another embodiment, the weighting coefficient included in the device setting policy set in the wireless terminal 10 may be determined as follows.
(R1) First, the acquisition information analysis unit 211 acquires information related to the type of communication application used for each radio bearer by each radio terminal connected to each of the radio networks 300 _{1 to} 300 _n . The communication application type used by each wireless terminal for each radio bearer is collected from the network device information collected from the wireless networks 300 _{1 to} 300 _n by the network information obtaining unit 221 and collected from each wireless terminal by the network information obtaining unit 221. Can be obtained based on the information.
(R2) Subsequently, the acquisition information analysis unit 211 is information on the degree of conformity between each of a plurality of different communication application types and a plurality of different RATs from among the operation policies provided by the operator / policy acquisition unit 222. To extract. For example, when the RAT is compatible with the LTE network, since the LTE network is a cellular radio network that is operated and managed by a mobile phone carrier, the security strength is high and an advanced QoS guarantee function compared to other RATs. Can be provided. Therefore, normally, in the above operation policy, the degree of conformity between the RAT corresponding to the LTE network and the communication application type requiring strict security and authentication such as online banking is set high. On the other hand, in the above operation policy, the degree of conformity between the RAT that is weak in security and authentication functions like public WiFi networks and the type of communication application that requires strict security and authentication like online banking is set low. Has been.
(R3) Subsequently, the acquired information analysis unit 211 can be used simultaneously from each wireless terminal according to the degree of conformity between the RAT corresponding to each wireless bearer and the communication application type used by each wireless bearer. A weighting factor is assigned to each of the one or more radio bearers.

  Finally, the policy distribution unit 212 in the external bearer setting unit 210 receives the device setting policy and base station information generated for setting in the radio terminal (UE) 10 from the acquisition information analysis unit 211, and receives the radio bearer 1 to radio Distribution to the wireless terminal 10 via one of the bearers N (step S1005 in FIG. 6). The base station information and the device setting policy distributed to the wireless terminal 10 are used by the wireless terminal 10 to select what the wireless terminal 10 uses for communication from a plurality of wireless bearers that can be used simultaneously. (Step S1006 in FIG. 6).

  As will be described later with reference to FIG. 7, the wireless terminal 10 performs the operation of selecting the one to be used for communication from a plurality of wireless bearers that can be used at the same time. There is a case of switching to a home type base station. In that case, the device setting policy to be set to the wireless terminal 10 from the policy distribution unit 212 is also distributed to the multihomed base station, and the multihomed base station uses the device setting policy at the same time. From among a plurality of possible radio bearers, the one used for communication with the radio terminal 10 is selected.

(6-2) Flow of Operation on Radio Terminal 10 Side First, the internal bearer setting unit 110 determines whether or not the bearer selection operation execution subject should be switched from the base station having the multihome function to the radio terminal 10 side. . In the bearer selection operation, a radio bearer to be used for user traffic transmission is selected from one or more radio bearers that can be used simultaneously by the radio terminal 10, and traffic allocation control is executed between these radio bearers. It is an operation. The internal bearer setting unit 110 can periodically perform an operation of determining whether or not to switch the execution subject of the bearer selection operation to the wireless terminal 10 side at regular time intervals. Further, as another embodiment, the internal bearer setting unit 110 detects the occurrence of a predetermined event event generated by software or hardware in the radio terminal (UE) 10, and according to the occurrence of the event event, It is possible to determine whether or not the execution subject of the bearer selection operation should be switched to the wireless terminal 10 side. It should be noted that the internal bearer setting unit 110 determines whether or not the bearer selection operation execution subject should be switched to the wireless terminal 10 side based on what criteria and in what method is shown in the flowchart of FIG. A specific description will be given later.

  The activation unit 113 is activated by the internal bearer setting unit 110 when the internal bearer setting unit 110 determines that the execution subject of the bearer selection operation should be switched to the wireless terminal 10 side. The activated activation unit 113 determines whether the switching unit 111 or the simultaneous communication processing unit 112 is to execute the bearer selection operation. The determining operation may be performed by the activating unit 113 according to a device setting policy set by the user in the radio terminal (UE) 10. When it is determined that the bearer selection operation is to be executed by the switching unit 111, the activation unit 113 sets the timing to start executing the function of selecting a single radio bearer to be used for communication from the radio bearers 1 to N. The switch unit 111 is instructed. Alternatively, when it is determined that the simultaneous communication processing unit 112 performs the bearer selection operation, the activating unit 113 performs traffic between one or more radio bearers used for communication among the radio bearers 1 to N. The simultaneous communication processing unit 112 is instructed to start execution of the optimal distribution.

  Subsequently, in the internal bearer setting unit 110, the switching unit 111 or the simultaneous communication processing unit 112 activated by the activation unit 113 performs a bearer selection operation. Specifically, the switching unit 111 first refers to the weighting coefficient for each radio bearer described in the device setting policy set in the wireless terminal 10 from the policy distribution unit 212, and corresponds to the maximum weighting coefficient. Select the radio bearer to be used. Subsequently, the switching unit 111 transmits an uplink signal via the selected radio bearer. On the other hand, the simultaneous communication processing unit 112 first refers to the weighting coefficient for each radio bearer described in the device setting policy set in the radio terminal 10 from the policy distribution unit 212, and can transmit for each radio bearer. The number of bits of the information signal is assigned according to the value of the weighting coefficient. Subsequently, the simultaneous communication processing unit 112 transmits an uplink signal by the number of bits allocated to each radio bearer via each radio bearer. Thereby, the simultaneous communication processing unit 112 optimizes the uplink and downlink traffic distribution among the plurality of radio bearers according to the weighting coefficient for each radio bearer.

  Thus, the bearer selection operation performed by the switching unit 111 or the simultaneous communication processing unit 112 uses the device setting policy and base station information distributed from the policy distribution unit 212 to the internal bearer setting unit 110 of the wireless terminal 10. And executed. Subsequently, the activated switching unit 111 or simultaneous communication processing unit 112 acquires, from the internal information acquisition unit 120, measurement values related to communication performance, communication settings, communication status, and the like inside the wireless terminal 10 for each radio bearer. . The information indicating the communication performance, communication settings, communication state, etc. of each radio bearer acquired from the internal information acquisition unit 120 includes (1) a transmission waiting state in the communication buffer for each radio bearer. The amount of transmission data in the downlink direction and the uplink direction, (2) communication control parameters and communication mode current settings for each radio bearer, (3) communication throughput achievement value to date for each radio bearer, and (4) The degree of communication service quality achieved for each radio bearer (communication delay, jitter, error retransmission frequency, etc.) is included.

  Subsequently, the activated switching unit 111 or simultaneous communication processing unit 112 performs a bearer selection operation in consideration of the measurement values regarding the communication performance, communication settings, communication state, and the like inside the wireless terminal 10 acquired from the internal information acquisition unit 120. Can be further adjusted. For example, the simultaneous communication processing unit 112 has a remarkably low communication service quality on the radio bearer or a frequency of error retransmission related to frame transmission on the radio bearer even if the radio bearer has a large weighting coefficient value. If it is high, the traffic allocation to the radio bearer can be reduced.

  In addition, when the internal bearer setting unit 110 switches the execution subject of the bearer selection operation to the multihomed base station in communication with the wireless terminal 10 based on the method described later with reference to FIG. The device setting policy set from 212 to the wireless terminal 10 is also distributed and set to the multihomed base station. As a result, the multihomed base station uses the weighting coefficient described in the device setting policy set in itself from the policy distribution unit 212 to switch the switching unit 111 and the simultaneous communication processing unit in the internal bearer selection unit 110. A bearer selection operation similar to that performed by 112 is performed. At that time, the device setting policy set by itself from the policy distribution unit 212 is that the bearer selection operation to be executed by the multihomed base station corresponds to either the switching unit 111 or the simultaneous communication processing unit 112. Is specified.

<7> Operation for determining whether or not to switch the execution subject of bearer selection operation to the wireless terminal side Hereinafter, when the wireless terminal 10 is communicating with a base station having a multihome function via one or more wireless bearers, A method for determining which of the base station side and the wireless terminal side is to be the execution subject of the bearer selection operation will be described with reference to the flowchart of FIG. When the internal bearer setting unit 110 is activated, the process proceeds to step S2001. In step S2001, the internal bearer setting unit 110 identifies all (m) radio bearers that the radio terminal 10 can use simultaneously. At the same time, among the base stations and wireless access points belonging to the wireless networks 300 _{1 to} 300 _n , the base station cell to which each of the identified m radio bearers is connected is identified by the cell ID. The identified m radio bearers and the cell IDs of the base station cells to which they are connected are associated in the form of a table as shown in FIG. The table in FIG. 8 showing the correspondence between the identified radio bearers and the base station cells to which they are connected is called terminal-side communication conditions. In the table of FIG. 8, the number m of radio bearers identified as being simultaneously available from the radio terminal 10 is four. In the table of FIG. 8, it can be seen that one radio bearer used for connection to the LTE network is connected to a cell of an LTE base station (eNodeB) having a cell ID = 100. In the table of FIG. 8, one of the two radio bearers used for connection with the wireless LAN (WiFi) is connected to the cell of the wireless LAN access point with the cell ID = 200, and the other is the cell ID = It can be seen that the wireless LAN access point cell 300 is connected. Further, in the table of FIG. 8, it can be seen that one radio bearer used for connection to the WiMAX network is connected to the cell of the WiMAX base station with the cell ID = 400.

  Then, a process progresses to step S2002 and the internal bearer setting part 110 extracts any one of cell ID enumerated by the terminal side communication conditions shown in the table | surface of FIG. Subsequently, the internal bearer setting unit 110 extracts a row including the same cell ID as the extracted cell ID in the base station information received from the policy distribution unit 212 as a linked cell list. For example, in the terminal-side communication conditions shown in the table of FIG. 8, the cell ID (cell ID = 100) of the cell to which the radio bearer corresponding to the LTE network is connected is “term” in the base station information shown in the table of FIG. This matches the “cell ID = 100” included in the row of “number = 1”. Accordingly, when the internal bearer setting unit 110 extracts the cell ID (cell ID = 100) of the cell connected to the radio bearer corresponding to the LTE network from the terminal-side communication conditions shown in the table of FIG. 8, the table shown in FIG. The row of “item number = 1” in the base station information is extracted as a linked cell list.

  Subsequently, the process proceeds to step S2003, and the internal bearer setting unit 110 sets each of the cell IDs listed in the terminal-side communication conditions shown in the table of FIG. 8 for the linked cells listed in the linked cell list. Match each cell ID. Specifically, the internal bearer setting unit 110 is configured so that each cell ID listed in the terminal-side communication condition shown in the table of FIG. 8 is any one cell listed as a linked cell in the linked cell list. It is determined whether or not it matches the ID. For example, the cell IDs of four cells listed in the terminal-side communication condition shown in the table of FIG. 8 are 100, 200, 300, and 400, respectively, and the item number = 1 in the base station information shown in the table of FIG. The linked cell lists corresponding to the rows are 100, 200, and 300. Therefore, in this case, the cell with cell ID = 400 listed in the terminal-side communication condition shown in the table of FIG. 8 does not match any cell listed in the linked cell list. That is, the cell with cell ID = 400 listed in the terminal-side communication condition shown in the table of FIG. 8 is not listed in the linked cell list. If all the cell IDs listed in the terminal-side communication condition match any one of the cell IDs listed in the linked cell list, it means that all the radio bearers that the radio terminal 10 targets for bearer selection operation However, it means that wireless connection is possible to any one of the cooperation cells that the multi-home type base station supports in a superimposed manner. Therefore, in this case, the radio terminal 10 is in a state where the execution of the bearer selection operation regarding one or more radio bearers that can be used simultaneously for connection to the radio network can be switched to the multihomed base station. Conversely, if at least one of all the cell IDs listed in the terminal-side communication condition is not listed in the linked cell list, the wireless terminal 10 is subject to at least one bearer selection operation target. For a radio bearer, this means that there is no linked cell corresponding to the base station side. Therefore, in this case, the radio terminal 10 must execute part or all of the bearer selection operation with respect to some or all of the radio bearers included in the terminal-side communication condition. If all the cell IDs listed in the terminal-side communication conditions shown in the table of FIG. 8 match any of the cell IDs listed in the linked cell list as a result of the above-described collation, the process proceeds to step S2005. Otherwise, the process proceeds to step S2004.

  In step S2004, the switching unit 111 or the simultaneous communication processing unit 112 in the wireless terminal 10 executes part or all of the bearer selection operation for some or all of the radio bearers included in the terminal-side communication condition. Details of the processing operation in step S2004 will be described later.

  In step S2005, the internal bearer setting unit 110 sets all cell IDs listed in the terminal-side communication condition shown in the table of FIG. 8 as all cell IDs listed as linked cells in the linked cell list. It is determined whether or not it corresponds to one to one. Specifically, the internal bearer setting unit 110 includes all cell IDs listed in the terminal-side communication condition shown in the table of FIG. 8 as all cell IDs listed as linked cells in the linked cell list. It is determined whether or not they match without excess or deficiency. As a result of this determination, if at least one of all cell IDs listed as linked cells in the linked cell list is not listed in the terminal-side communication conditions shown in the table of FIG. Means that. That is, at least one unconnected cell to which the radio terminal 10 is not connected via the radio bearer is included in the linked cells on the base station side. As a result of this determination, if at least one of all cell IDs listed as linked cells in the linked cell list is not listed in the terminal-side communication conditions shown in the table of FIG. 8, the process proceeds to step S2006. Otherwise, the process proceeds to step S2007.

  In step S2006, the internal bearer setting unit 110 performs a cell search for the above-mentioned unconnected cells among the linked cells supported in a superimposed manner by the base station side. Specifically, the internal bearer setting unit 110 supplements the carrier signal transmitted from the unconnected cell described above, and wirelessly connects to the unconnected cell described above using any one of the radio bearers. Subsequently, the internal bearer setting unit 110 adds a new entry corresponding to the cell ID of the wirelessly connected unconnected cell to the terminal-side communication condition shown in the table of FIG. As a result, all cell IDs listed in the terminal-side communication conditions shown in the table of FIG. 8 match all cell IDs listed as linked cells in the linked cell list without excess or deficiency. 10 can effectively use all the linked cells provided by the multi-homed base station without omission.

  In step S2007, the internal bearer setting unit 110 turns off the bearer selection operation in the radio terminal 10. Specifically, the internal bearer setting unit 110 outputs a disable signal to the switching unit 111 and the simultaneous communication processing unit 112 that perform a bearer selection operation on the wireless terminal 10, and the switching unit 111 and the simultaneous communication processing unit The operation of 112 is stopped. Subsequently, the internal bearer setting unit 110 performs the same processing as the bearer selection operation to be performed by the switching unit 111 or the simultaneous communication processing unit 112 with respect to the multihomed base station in communication with the wireless terminal 10. Request.

  The detailed contents of the processing operation in step S2004 described above will be described as follows. If at least two of the m (m> 3) cells listed in the terminal-side communication condition shown in the table of FIG. 8 are listed in the linked cell list, connect to the at least two cells. As for the radio bearer, it is possible to execute a bearer selection operation on the multi-homed base station side. On the other hand, for radio bearers corresponding to one or more cells not listed in the linked cell list among m (m> 3) cells listed in the terminal-side communication conditions shown in the table of FIG. The bearer selection operation needs to be executed on the wireless terminal 10 side.

  Therefore, in such a case, with respect to some radio bearers included in the terminal-side communication condition, the radio terminal 10 performs part of the bearer selection operation, and performs the remaining bearer selection operation with respect to the remaining radio bearers. Will be executed. Further, the radio terminal 10 is also between two or more radio bearers targeted for bearer selection operation in the multihomed base station and one or more radio bearers targeted for bearer selection operation in the radio terminal 10. Need to perform a bearer selection operation.

  Eventually, in step S2004, the switching unit 111 or the simultaneous communication processing unit 112 in the radio terminal 10 executes part or all of the bearer selection operation for some or all radio bearers included in the terminal-side communication condition, The sharing of the bearer selection operation between the radio terminal 10 and the base station side is as described above.

  For example, the cell IDs of four cells listed in the terminal-side communication condition shown in the table of FIG. 8 are 100, 200, 300, and 400, respectively, and the item number = 1 in the base station information shown in the table of FIG. The linked cell lists corresponding to the rows are 100, 200, and 300. Therefore, in this case, the cell with cell ID = 400 listed in the terminal-side communication condition shown in the table of FIG. 8 does not match any cell listed in the linked cell list. That is, the cell with cell ID = 400 listed in the terminal-side communication condition shown in the table of FIG. 8 is not listed in the linked cell list. Accordingly, among the four radio bearers connected to the four cells listed in the terminal-side communication conditions shown in the table of FIG. 8, three radio bearers corresponding to the three cells having cell ID = 100, 200 and 300 The bearer selection operation for the target can be executed on the base station side. On the other hand, the bearer selection operation between the three radio bearers and the radio bearer corresponding to the cell ID = 400 needs to be executed in the radio terminal 10.

  In the above description of the present embodiment, the cell ID is used as a cell identifier for identifying each cell. However, in an alternative embodiment, a PSC (Primary) unique to each cell is used. It is also possible to use Synchronization Code) or PCI (Physical Channel Identifier) as a cell identifier.

<8> Effects of the present embodiment This embodiment performs the above-described connection switching and traffic distribution between linked cells when implementing policy control that adaptively controls communication paths in a wireless network according to the situation. A mechanism to execute can be realized. Further, in the present embodiment, when performing policy control that adaptively controls a communication path in a wireless network according to a situation, a bearer selection operation executed on the base station side and the wireless terminal 10 side Can be realized. Specifically, when the multihomed base station with which the radio terminal 10 is communicating supports a plurality of cells corresponding to different RATs in a superimposed manner, the present embodiment provides a plurality of cells connected to the plurality of cells. The bearer selection operation between the radio bearers can be switched from the radio terminal 10 to the base station side. Accordingly, in the present embodiment, the bearer selection operation between a plurality of radio bearers that can be used simultaneously for the radio terminal 10 to connect to the radio network is shared between the radio terminal 10 and the multihomed base station. Can be executed. In addition, the present embodiment relates to the above-described path control. In the wireless network managed by the same policy control node, even if the number of connected wireless terminals and the execution frequency of the policy control operation increase, It is possible to realize policy control that does not increase the control overhead.

  The present invention improves the communication service quality and communication throughput by efficiently using a wide variety of line connections available on the wireless network side in a mobile wireless terminal that can simultaneously use a plurality of different types of wireless connection means. Can be used as a wireless communication control software or a wireless communication control device.

10 Radio terminal (UE)
DESCRIPTION OF SYMBOLS 20 Server which provides network service to a radio | wireless terminal (UE) 30 Radio bearer 40 Radio access network 51 Core network 52 Core network 53 ISP network 54 Router network 61 Core network gateway 62 Core network gateway 71 External connection gateway 72 External connection gateway 80 Internet network 90 Base station or wireless access point 91 Wireless communication carrier network 101 Antenna 102 Wireless interface 103 Memory 104 Control processor 105 User input / output device 106 Storage 107 Bus 110 Internal bearer setting unit 111 Switching unit 112 Simultaneous communication processing unit 113 Activating unit DESCRIPTION OF SYMBOLS 120 Internal information acquisition part 200 Policy control mechanism 210 External bearer setting part 211 Acquisition information analysis part 212 Policy distribution part 220 External information acquisition part 21 network information acquisition unit 222 Operator policy acquisition unit 230 operating system

Claims (9)

A method of optimally allocating user traffic among a plurality of radio bearers while simultaneously communicating in parallel between one or more base stations and radio terminals via a plurality of radio bearers:
Comparing base station information received from a radio network with a list of cells to which the radio terminal is connected via the plurality of radio bearers;
As a result of the comparison, when any of the base stations supports two or more cells to which two or more of the plurality of radio bearers are connected in a superimposed manner, an execution source of the process of allocating the optimal ratio Switching between the supporting base station and the wireless terminal; and
The supporting base station or the wireless terminal determining a distribution for optimally allocating the user traffic among the radio bearers based on a policy set from the wireless network;
A method comprising: A method of transmitting user traffic over a radio bearer selected from a plurality of radio bearers that can be used simultaneously between one or more base stations and a radio terminal:
Comparing base station information received from a radio network with a list of base stations to which the radio terminal is connected via the plurality of radio bearers;
As a result of the comparison, when any one of the base stations supports two or more cells to which two or more of the plurality of radio bearers are connected in a superimposed manner, a process of selecting the radio bearer is executed. Switching the source between the supporting base station and the wireless terminal; and
The supporting base station or the radio terminal selects a radio bearer from the plurality of radio bearers based on a policy set from the radio network, and transmits the user traffic on the selected radio bearer. Transmitting step;
A method comprising: The base station information includes a table that lists one or more cells that each of the one or more base stations support in a superimposed manner, and the one or more cells correspond to different RATs,
In the switching step, if, as a result of the comparison, the set of cells listed in the base station information and the set of cells included in the list of cells to which the wireless terminal is connected partially overlap or all overlap:
Selecting a radio bearer from the plurality of radio bearers and transmitting user traffic on the selected radio bearer; or
A process of optimally allocating the user traffic among the plurality of radio bearers;
The method according to claim 1, further comprising the step of switching a part or all of the execution to a side of the supporting base station. Determining the allocation comprises allocating the amount of user traffic among radio bearers according to a weighting factor for each radio bearer described by the policy set from the radio network;
The weighting factor is determined for each radio bearer by a policy control mechanism in the radio network according to a communication load on a communication path corresponding to each radio bearer, or
The weighting factor is determined for each radio bearer by a policy control mechanism in the radio network according to the degree of conformity between the communication application type used in each radio bearer and the radio access technology supported by each radio bearer. ,
The method of claim 1 wherein: The step of selecting a radio bearer from the plurality of radio bearers and transmitting the user traffic on the selected radio bearer includes a weighting factor for each radio bearer described by the policy set from the radio network And selecting a radio bearer corresponding to the largest weighting factor according to
The weighting factor is determined for each radio bearer by a policy control mechanism in the radio network according to a communication load on a communication path corresponding to each radio bearer, or
The weighting factor is determined for each radio bearer by a policy control mechanism in the radio network according to the degree of conformity between the communication application type used in each radio bearer and the radio access technology supported by each radio bearer. ,
The method of claim 2. An internal bearer setting unit provided in a radio terminal that communicates with one or more base stations via a plurality of radio bearers simultaneously in parallel, and distributes user traffic among the plurality of radio bearers in an optimal ratio for:
Means for comparing base station information received from a radio network with a list of cells to which the radio terminal is connected via the plurality of radio bearers;
As a result of the comparison, when any of the base stations supports two or more cells to which two or more of the plurality of radio bearers are connected, the execution is supported for the process of allocating the optimal ratio. Means for switching between a base station and the wireless terminal; and
A simultaneous communication processing unit for optimally allocating the user traffic among radio bearers based on a policy set by the radio network when execution of the process of allocating the optimal ratio is switched to the radio terminal;
An internal bearer setting unit. An internal bearer setting unit provided in a wireless terminal that selectively uses one of a plurality of radio bearers that can be used simultaneously with one or more base stations and transmits user traffic:
Means for comparing base station information received from a radio network with a list of cells to which the radio terminal is connected via the plurality of radio bearers;
As a result of the comparison, if any of the base stations supports two or more cells to which two or more of the plurality of radio bearers are connected, a radio bearer is selected from the plurality of radio bearers. Means for switching an entity to perform between the supporting base station and the wireless terminal; and
A switching unit that optimally distributes the user traffic among the radio bearers based on a policy set by the radio network when the subject that selects the radio bearer is switched to the radio terminal;
An internal bearer setting unit. A wireless terminal comprising the simultaneous communication processing unit according to claim 6, the switching unit according to claim 7, and an activation unit,
In order to transmit user traffic using one or more of a plurality of radio bearers respectively connected to one or more base stations, the activating unit selects either the simultaneous communication processing unit or the switching unit. Start automatically,
A wireless terminal characterized by that. The activation unit selectively activates either the simultaneous communication processing unit or the switching unit based on the policy set by the user for the wireless terminal. Including an operation in which the activating unit determines which one to activate.
The wireless terminal according to claim 8.

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