Patent Application
20150282009
The present application relates to a mobile communication system, and in particular, to management of terminal information used in a radio access network.
A multiple access mobile communication system enables a plurality of wireless terminals to perform wireless communication substantially simultaneously, by sharing radio resources including at least one of time, frequency, and transmission power among the plurality of mobile terminals. Typical examples of multiple access schemes include Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), or Orthogonal Frequency Division Multiple Access (OFDMA) and any combination thereof. Unless otherwise explained, the term “mobile communication system” used in this specification refers to a multiple access mobile communication system.
A mobile communication system includes a mobile terminal and a network. The network includes a radio access network (RAN) and a mobile core network (MCN). The mobile terminal communicates with an external network (e.g., the Internet, a packet data network, or a private enterprise network) through the RAN and the MCN. The mobile communication system is, for example, a 3rd Generation Partnership Project (3GPP) Universal Mobile Telecommunications System (UMTS) or an Evolved Packet System (EPS). The RAN is, for example, a Universal Terrestrial Radio Access Network (UTRAN) or an Evolved UTRAN (E-UTRAN). The MCN is, for example, a General Packet Radio Service (GPRS) packet core or an Evolved Packet Core (EPC).
Patent literature 1 discloses measuring, by a mobile terminal or a network (i.e., a base station or a gateway), duration time of an inactive state during which the mobile terminal does not perform communication, and causing the mobile terminal to make a transition to a sleep mode when the duration time exceeds a predetermined expiration period. Patent literature 1 further discloses measuring, by a mobile terminal or a network (i.e., a base station or a gateway), an occurrence rate of communication of the mobile terminal, and changing the expiration period of the timer regarding the sleep mode transition according to the occurrence rate of communication of the mobile terminal. Patent literature 1 further discloses changing the expiration period of the timer regarding the sleep mode transition based on remaining battery power of the mobile terminal.
Patent literature 2 and 3 disclose supplying, from an MCN to a control apparatus (e.g., a base station) in a RAN, a control policy used to control a state transition of a mobile terminal between a CONNECTED state and an IDLE state. The control policy includes, for example, designation of a time interval (IDLE transition interval) until the time that the mobile terminal makes a transition from the CONNECTED state to the IDLE state. The control policy is managed, for example, by a mobility management node (e.g., a Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN)) or a subscriber server (e.g., a Home Subscriber Server (HSS)).
Non-patent literature 1 and 2 disclose that subscriber data managed by an HSS in a 3GPP mobile communication system includes configuration data of an UE inactivity timer. The UE inactivity timer measures duration time of an inactive state during which user data regarding a mobile terminal is neither transmitted nor received. The UE inactivity timer is started by a base station and is used to determine to change the state of the mobile terminal from a CONNECTED state to an IDLE state. The configuration data of the UE inactivity timer held by the HSS is sent to the base station from the HSS through a Mobility Management Entity (MME) in response to attaching of the mobile terminal, a location registration update, a service request or the like.
The following are definitions of the terms “CONNECTED state” and “IDLE state” used in this specification and Claims. The “IDLE state” means a state in which a mobile terminal does not continuously send or receive control signals for session management and mobility management to or from an MCN, and radio connections in a RAN have been released. An example of the IDLE state is an EPS Connection Management IDLE (ECM-IDLE) state and a Radio Resource Control IDLE (RRC_IDLE) state of the 3GPP. In the RRC_IDLE, RRC Connection, which is a radio connection in the E-UTRAN, is released.
Meanwhile, the “CONNECTED state” means a state in which, as in an ECM-CONNECTED state and an RRC_CONNECTED state of the 3GPP, a radio connection at least for sending and receiving control signals (control messages) for session management and mobility management between the mobile terminal and the MCN is established in a RAN, and such a connection is established as to be able to send and receive control signals (control messages) between the mobile terminal and the MCN. In short, it is only necessary that the “CONNECTED state” is a state in which the mobile terminal is connected to the MCN so as to be able to at least send and receive the control signals (control messages) for the session management and the mobility management. The “CONNECTED state” may be a state in which a data bearer is configured for transmitting and receiving user data between the mobile terminal and an external packet data network (PDN). Alternatively, the “CONNECTED state” may be a state in which the mobile terminal does not have the data bearer though it has the control connection with the MCN. The “CONNECTED state” can also be called an “ACTIVE state”.
Typically, the MCN tracks the location of a CONNECTED state mobile terminal with a cell level granularity, and tracks the location of an IDLE state mobile terminal with a registration area level granularity. The registration area (e.g., a tracking area or a routing area) includes a plurality of cells. When moved from one location registration area to another location registration area, a mobile terminal which is in the IDLE state sends to the MCN a message indicating an update of the location registration area. Upon arrival of downlink traffic (downlink data or incoming voice call) to the mobile terminal which is in the IDLE state, the MCN sends a paging signal to a paging area defined based on the location registration area.
In this specification, a timer that measures a duration time of the inactive state, during which data of a mobile terminal is neither transmitted nor received, to determine a transition of a mobile terminal from the CONNECTED state to the IDLE state is referred to as a “UE inactivity timer” according to the terminology used in the 3GPP.
The present inventors have examined measurements of mobile terminal behavior (e.g., an occurrence rate of communication or an occurrence rate of movement) in a RAN (e.g., a base station or a Radio Network Controller (RNC)) and a determination of an appropriate timer value (expiration period) of a UE inactivity timer for each mobile terminal (or each mobile terminal group) based on the measurement results, and have found various problems from the examination. One of these problems is that, when a mobile terminal makes a transition to the IDLE state, the RAN (e.g., a base station or an RNC) stops acquisition and update of RAN terminal information regarding the mobile terminal and releases the RAN terminal information retained until then. The RAN terminal information includes, for example, at least one of (a) measurement information regarding the mobile terminal acquired in the RAN; (b) history information regarding the mobile terminal acquired in the RAN; and (c) configuration information regarding the mobile terminal determined in the RAN. Accordingly, for example, it is difficult for the RAN to collect the measurement information or the history information regarding the mobile terminal for a time period over a plurality of CONNECTED-IDLE transitions and to perform a setting regarding the mobile terminal (e.g., the UE inactivity timer value) based on this long-term information. Further, the RAN does not retain any of measurement information and history information regarding a mobile terminal at the time just after the mobile terminal has made a transition to the CONNECTED state, and thus the RAN cannot perform a setting (e.g., an UE inactivity timer value) regarding the mobile terminal based on the measurement information or the history information.
That the RAN terminal information retained in the RAN is released in response to the transition of the mobile terminal to the IDLE state can be a problem in other cases than the case of determination of the UE inactivity timer value. In other words, that the RAN cannot continuously use the RAN terminal information (e.g., measurement information or history information) for a time period over a plurality of CONNECTED-IDLE transitions may generally be a problem when the RAN performs some decisions or settings regarding the mobile terminal. The decisions or the settings regarding the mobile terminal in the RAN includes, for example, determination of initiation of a handover, determination of a handover target cell, and determination of a back-off time in a random access procedure.
Patent literature 1 discloses measuring, in a base station, an occurrence rate of communication of a mobile terminal and changing an expiration period of a timer regarding sleep-mode transition according to the occurrence rate of communication of the mobile terminal. Patent literature 1, however, does not teach any method for retaining and continuously using measurement information of the occurrence rate of communication.
Accordingly, an object of the present invention is to provide apparatuses, systems, methods, and programs which have been improved to enable a RAN to continuously use RAN terminal information (e.g., measurement information or history information) for a time period over a plurality of CONNECTED-IDLE transitions.
In a first aspect, a radio access network apparatus arranged in a radio access network includes an information management unit. The information management unit is configured to send, to a core network, RAN terminal information regarding a mobile terminal, and is further configured to receive the RAN terminal information from the core network.
In a second aspect, a core network apparatus arranged in a core network includes a control unit. The control unit is configured to receive, from a radio access network, RAN terminal information regarding a mobile terminal, and is further configured to send the RAN terminal information to the radio access network.
In a third aspect, a mobile terminal includes a radio communication unit. The radio communication unit is used in combination with a base station according to the first aspect described above, and is configured to communicate with the base station, which retains the RAN terminal information, in accordance with a setting by the base station.
In a fourth aspect, a method performed by a radio access network apparatus includes sending, to a core network, RAN terminal information regarding a mobile terminal.
In a fifth aspect, a method performed by a core network apparatus includes receiving, from a radio access network, RAN terminal information regarding a mobile terminal and sending the RAN terminal information to the radio access network.
In a sixth aspect, a program includes instructions to cause a computer to perform the method according to the fourth aspect stated above.
In a seventh aspect, a program includes instructions to cause a computer to perform the method according to the fifth aspect stated above.
In the first to seventh aspects stated above, the RAN terminal information includes at least one of: (a) measurement information regarding the mobile terminal acquired in the radio access network; (b) history information regarding the mobile terminal acquired in the radio access network; and (c) configuration information regarding the mobile terminal determined in the radio access network.
According to the first to seventh aspects stated above, it is possible to provide apparatuses, systems, methods, and programs which have been improved to enable a RAN to continuously use RAN terminal information (e.g., measurement information or history information) for a time period over a plurality of CONNECTED-IDLE transitions.
Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, the same or corresponding components are denoted by the same reference symbols, and repetitive explanations will be omitted as appropriate for the sake of clarification.
The RAN 20 includes a base station 100 and a radio resource management function. The radio resource management function may be arranged in a RAN node other than the base station 100, or may be arranged in the base station 100. For example, in a 3GPP Universal Mobile Telecommunications System (UMTS), the radio resource management function is arranged in an RNC. Meanwhile, in a 3GPP Evolved Packet System (EPS), the radio resource management function is arranged in a base station (eNB). The RAN 20 is, for example, an E-UTRAN or a UTRAN, or the combination thereof.
The base station 100 is connected to a mobile terminal 200 by means of a radio access technology. In the E-UTRAN, the base station 100 corresponds to an E-UTRAN NodeB (eNB). In the UTRAN, the base station 100 corresponds to the functions of a NodeB and a Radio Network Controller (RNC). The base station 100 sends and receives control messages (e.g., S1 Application Protocol (S1AP) messages) to and from a mobility management node 300 in the MCN 30 and transmits and receives user data (or tunnel packets in which the user data is encapsulated) to and from a transfer node 310 in the MCN 30.
The mobile terminal 200 has a radio interface, is connected to the base station 100 by means of a radio access technology, and is also connected to the MCN 30 through the RAN 20 (i.e., base station 100). The mobile terminal 200 communicates with an external network 40 through the RAN 20 and the MCN 30. The external network 40 includes the Internet, a packet data network, a PSTN, or any combination thereof. Further, the mobile terminal 200 sends and receives Non-Access Stratum (NAS) messages to and from a control node (e.g., mobility management node 300) in the MCN 30. The NAS messages are control messages that are not terminated at the RAN 20 and are transparently transferred between the mobile terminal 200 and the MCN 30 without depending on the radio access technology in the RAN 20. The NAS messages transmitted from the mobile terminal 200 to the MCN 30 include NAS request messages such as a location update request, a session (bearer) request, and an attach request. In the case of the EPS, for example, the NAS request messages from the mobile terminal 200 include at least one of an Attach Request, a Service Request, a PDN connectivity request, a Bearer Resource Allocation Request, a Bearer Resource Modification Request, a Tracking Area Update (TAU) Request, and a Routing Area Update (RAU) Request. Meanwhile, the NAS messages transmitted from the MCN 30 to the mobile terminal 200 include ACCEPT and REJECT messages as replies to these NAS request messages.
The MCN 30 is a network mainly managed by an operator that provides mobile communication services. The MCN 30 is a Circuit Switched (CS) core or a Packet Switched (PS) core, or a combination thereof. The MCN 30 is, for example, an EPC in the EPS, or a General Packet Radio Service (GPRS) packet core in the UMTS, or a combination thereof. In the example shown in
The mobility management node 300 is a control-plane node, and performs mobility management (e.g., location registration) of the mobile terminal 200, session (bearer) management (e.g., bearer establishment, bearer modification, and bearer release) and the like. The mobility management node 300 sends and receives control messages (e.g., S1AP messages) to and from the base station 100 and sends and receives NAS messages to and from the mobile terminal 200. In the case of the UMTS, for example, the mobility management node 300 includes control plane functions of an SGSN. In the case of the EPS, the mobility management node 300 includes an MME.
The transfer node 310 provides a user plane function including transfer of user data or circuit switching between the mobile terminal 200 and the external network 40. In the case of the UMTS, for example, the transfer node 310 includes user plane functions of an MSC, user plane functions of an SGSN, and a Gateway GPRS Support Node (GGSN). In the case of the EPS, the transfer node 310 includes a Serving Gateway (S-GW) and a PDN Gateway (P-GW).
The subscriber server 320 is a database that retains subscriber data regarding the mobile terminal 200. The subscriber server 320 corresponds, for example, to a Home Subscriber Server (HSS) or a Home Location Register (HLR). The subscriber server 320 sends the subscriber data to the mobility management node 300 in response to a request from the mobility management node 300.
The base station 100 according to this embodiment acquires RAN terminal information (RAN UE Context) regarding the mobile terminal 200 and performs a setting regarding the mobile terminal 200 using the RAN terminal information. Further, the base station 100 is configured to send the acquired RAN terminal information to the MCN 30 in order to save the RAN terminal information in the MCN 30, and is also configured to receive the saved RAN terminal information from the MCN 30 in order to read out (i.e., retrieve) the RAN terminal information. The RAN terminal information sent to the base station 100 from the MCN 30 may be information that have been acquired by another base station 100 and have been saved in the MCN 30.
Now, the term “RAN terminal information” used in this specification will be defined. The RAN terminal information in this specification is information regarding the mobile terminal 200 acquired or determined in the RAN 20 and includes at least one of the following (a) to (c):
(a) measurement information regarding the mobile terminal 200 acquired in the RAN 20;
(b) history information regarding the mobile terminal 200 acquired in the RAN 20; and
(c) configuration information regarding the mobile terminal 200 determined in the RAN 20.
The above information (a) to (c) may be acquired or determined for each mobile terminal 200 or may be acquired or determined for each terminal group. The terminal group may be defined, for example, by a unit of a terminal type, a unit of a service used by the mobile terminal 200, or a unit of a Quality of Service (QoS) class requested by the mobile terminal 200. When the terminal group is defined by a unit of a QoS class, a QoS Class Indicator (QCI) may be used as an index. Further, the above information (a) to (c) may be managed on a time basis for the mobile terminal 200. By managing the information (a) to (c) on a time basis, it is possible to finely manage the mobile terminal according to the behavior of the mobile terminal 200. Specific examples of the information (a) to (c) as the RAN terminal information will be described below.
The RAN 20 (e.g., the base station 100) can acquire measurement information indicating behavior of the mobile terminal 200 such as communication properties, moving properties, or handover properties of the mobile terminal 200. For example, the RAN 20 can measure a communication duration time, a communication frequency band, a communication interval (a non-communication time), occurrence rate of communication, Modulation and Coding Schemes (MCS), a communication data amount, throughput, a communication delay, packet loss, a discarded packet amount, or a type of service to be used, or any statistical value thereof (e.g., an average value, a median value, a maximum value, a minimum value) regarding the communication of the mobile terminal 200. The communication properties of the mobile terminal 200 may be measured on a radio bearer or may be measured on a bearer between the RAN 20 and the MCN 30 (e.g., 51 bearer or EPS Radio Access Bearer (E-RAB)). The RAN 20 may acquire such information indicating the communication properties of the mobile terminal 200 as measurement information regarding the mobile terminal 200. The RAN 20 can acquire information indicating moving properties of the mobile terminal 200 (e.g., history of cells (or base stations) in which the mobile terminal 200 stayed, time during which the mobile terminal 200 stayed in a cell (or a base station), a moving speed, or a moving vector, or any statistical value thereof. The RAN 20 may acquire such information indicating the moving properties of the mobile terminal 200 as the measurement information regarding the mobile terminal 200. The RAN 20 can also acquire information indicating handover properties of the mobile terminal 200 (e.g., the number of handover attempts, the number of times of handover failure (e.g., Too Late Handovers or Too Early Handovers), or a handover failure rate, or any statistical value thereof. The RAN 20 may acquire such information indicating the handover properties of the mobile terminal 200 as the measurement information regarding the mobile terminal 200.
The RAN 20 (e.g., the base station 100) can acquire history information indicating behavior of the mobile terminal 200 such as communication properties or moving properties of the mobile terminal 200. The history information regarding the mobile terminal 200 includes, for example, at least one of a communication history of the mobile terminal 200, a movement history of the mobile terminal 200, and a service usage history of the mobile terminal 200. Note that the history information regarding the mobile terminal 200 and the measurement information regarding the mobile terminal 200 may not be clearly distinguished from each other. At least a part of the measurement information regarding the mobile terminal 200 stated above may be called history information regarding the mobile terminal 200.
The RAN 20 can perform a setting regarding the mobile terminal 200 using the measurement information or the history information regarding the mobile terminal 200 described above. The setting performed by the RAN 20 includes, for example, a timer value (expiration period) of an UE INACTIVITY TIMER, handover parameters (e.g., an A3-offset and a Time to Trigger (TTT)), a back-off time in a random access procedure, (an average value of) an access restriction time during which an access to a base station is restricted (ac-BarringTime), or a terminal priority. The terminal priority indicates the priority of the mobile terminal 200 (or the terminal group) with respect to other mobile terminals (or terminal groups), and is used, for example, in determination of the aforementioned configuration information (a timer value of an UE INACTIVITY TIMER, handover parameters, or a back-off time in a random access procedure) or in radio resource allocation.
As stated above, the base station 100 is configured to save the RAN terminal information (e.g., measurement information, history information), which has been obtained in the RAN 20, in the MCN 30. The base station 100 is further configured to read out the RAN terminal information saved in the MCN 30 from the MCN 30. Accordingly, even when the RAN 20 has released (deleted) the RAN terminal information according to a transition of the mobile terminal 200 to the IDLE state, the base station 100 can read out and use the saved RAN terminal information, which has been saved in the MCN 30, for the following settings of the mobile terminal 200. In other words, the base station 100 can continuously use the RAN terminal information for a time period over a plurality of CONNECTED-IDLE transitions of the mobile terminal 200. Accordingly, the base station 100 can perform a setting regarding the mobile terminal 200 (e.g., settings of a timer value of an UE INACTIVITY TIMER) in consideration of the long-term RAN terminal information regarding the mobile terminal 200.
In the following description, specific examples of when the RAN terminal information is saved in the MCN 30 from the RAN 20 and examples of when the RAN terminal information is read out from the MCN 30 to the RAN 20 will be described. As already described above, in a typical mobile communication system, the RAN (e.g., a base station or an RNC) stops, at the time of the transition of the mobile terminal to the IDLE state, acquisition and update of the RAN terminal information regarding the mobile terminal and releases the RAN terminal information retained until then. Accordingly, for example, when releasing the RAN terminal information regarding the mobile terminal 200, the base station 100 may send the information to the MCN 30. To be more specific, the base station 100 may send the RAN terminal information to the MCN 30 in response to cessation of autonomous acquisition of the RAN terminal information in the base station 100. Alternatively, the base station 100 may send, to the MCN 30, the RAN terminal information regarding the mobile terminal 200 in response to a transition of the mobile terminal 200 from the CONNECTED state to the IDLE state. Further alternatively, the base station 100 may send, to the MCN 30, the RAN terminal information regarding the mobile terminal 200 in response to an outgoing handover of the mobile terminal 200 from one of its own cells to a cell of another base station. By sending the RAN terminal information to the MCN 30 at any of these timings, the base station 100 can save, in the MCN 30, the RAN terminal information to be released (or deleted).
Meanwhile, the base station 100 may receive, from the MCN 30, the saved RAN terminal information regarding the mobile terminal 200 in response to initiation (re-start) of autonomous acquisition of the RAN terminal information regarding the mobile terminal 200. To be more specific, the base station 100 may receive from the MCN 30 the RAN terminal information regarding the mobile terminal 200 in response to a transition of the mobile terminal 200 from the IDLE state to the CONNECTED state. Alternatively, the base station 100 may receive from the MCN 30 the RAN terminal information regarding the mobile terminal 200 in response to an incoming handover of the mobile terminal 200 to one of its own cells from a cell of another base station. According to any one of the above operations, the base station 100 can continuously use the RAN terminal information of the mobile terminal 200 (e.g., measurement information, history information, or configuration information) for a time period over a plurality of CONNECTED-IDLE transitions.
The above examples of when the RAN terminal information is saved in the MCN 30 from the RAN 20 and examples of when the RAN terminal information is read out from the MCN 30 to the RAN 20 are merely preferable examples. For example, when a signaling for a location update or the like of the mobile terminal 200 occurs between the base station 100 and the MCN 30, the base station 100 may send the RAN terminal information regarding the mobile terminal 200 to the MCN 30. In this case, the base station 100 may add the RAN terminal information into the control message to be sent to the mobility management node 300 for the location update, for example. By adding the RAN terminal information in the existing control message sent from the RAN 20 to the MCN 30, there is no need to send a new control message, and thus it is possible to suppress an increase in the number of times of signaling due to the saving of the RAN terminal information in the MCN 30. Further, the base station 100 may send the RAN terminal information to the MCN 30 at any time, such as when the RAN terminal information is updated.
Next, management entities of the RAN terminal information in the MCN 30 will be described. As an example, the mobility management node 300 may manage the RAN terminal information. The mobility management node 300 has a signaling interface with the RAN 20 (e.g., base station 100). Further, the mobility management node 300 retains a context regarding the mobile terminal 200 in the IDLE state in order to perform mobility management of this mobile terminal 200. Accordingly, the mobility management node 300 manages the RAN terminal information in association with, for example, the context regarding the mobile terminal 200, whereby it is possible to easily manage the RAN terminal information in the MCN 30. The RAN terminal information, however, may be retained in another node in the MCN 30 (e.g., the subscriber server 320). Since the subscriber server 320 retains the subscriber information regarding the mobile terminal 200, the subscriber server 320 may retain the RAN terminal information in association with the subscriber information. Further, since the subscriber server 320 typically has a signaling interface with the mobility management node 300, the subscriber server 320 may receive the RAN terminal information from the base station 100 through the mobility management node 300.
Further, the mobility management node 300 may release (delete) the RAN terminal information, which has been saved in the mobility management node 300 regarding the mobile terminal 200, in response to a detach of the mobile terminal 200 from the MCN 30. Since the mobility management node 300 performs mobility management of the mobile terminal 200, the mobility management node 300 is able to easily recognize a detach of the mobile terminal 200. Release of the RAN terminal information regarding detached mobile terminal 200 can contribute to suppression of the volume of the RAN terminal information accumulated in the MCN 30. Alternatively, the mobility management node 300 may also save the RAN terminal information, which has been saved in the mobility management node 300, in the subscriber server 320 in response to a detach of the mobile terminal 200 from the MCN 30. According to such an operation, the subscriber server 320 can retain the latest RAN terminal information.
In the following description, specific examples of a method of saving the RAN terminal information in the MCN 30 according to this embodiment and a method of reading out the RAN terminal information from the MCN 30 will be described with reference to sequence diagrams.
As already described above, the base station 100 may save the RAN terminal information regarding the mobile terminal 200 in the MCN 30 in response to the transition of the mobile terminal 200 from the CONNECTED state to the IDLE state.
The example shown in
The sequences of the method of saving the RAN terminal information shown in
Next, an operation for reading out the RAN terminal information saved in the MCN 30 to the base station 100 will be described.
As already described above, the base station 100 may receive the RAN terminal information regarding the mobile terminal 200 from the MCN 30 in response to the transition of the mobile terminal 200 from the IDLE state to the CONNECTED state.
The sequence of the method of reading out the RAN terminal information shown in
Further, the mobility management node 300 may send the RAN terminal information, received from one base station 100 and stored in the mobility management node 300, to another base station 100. For example, the mobility management node 300 may send the RAN terminal information, received from a first base station and saved in the mobility management node 300, to a second base station in response to a movement of the mobile terminal 200 from the first base station to the second base station. Accordingly, the base station 100 can perform a setting of the mobile terminal 200 using the RAN terminal information collected by another base station even when the base station 100 does not have any RAN terminal information acquired by itself.
In the following description, an operation of the base station 100 according to this embodiment will be described with reference to flowcharts.
If the timer value of the UE INACTIVITY TIMER is too short, signaling for the IDLE-CONNECTED transition of the mobile terminal 200 frequently occurs and the signaling load (signaling cost) in the RAN 20 and the MCN 30 increases. On the other hand, if the timer value of the UE INACTIVITY TIMER is too long, radio resources reserved for the mobile terminal 200 which is not performing communication are wasted (i.e., a radio resource cost is large). Accordingly, it is preferable that the timer value of the UE INACTIVITY TIMER be optimized according to the communication status of the mobile terminal 200. For example, the timer value of the UE INACTIVITY TIMER may be determined by optimizing a cost function defined using the average non-communication time (average communication interval) and the average communication time of the mobile terminal 200. By saving the RAN terminal information in the MCN 30 and reading out the RAN terminal information from the MCN 30, the base station 100 can easily and continuously acquire the statistical value related to the communication properties of the mobile terminal 200, such as the average non-communication time (average communication interval) and the average communication time, for a time period over a plurality of CONNECTED-IDLE transitions.
In the following description, configuration examples of the base station 100 and the mobility management node 300 will be described.
The UE inactivity timer 105 is a timer that measures a duration time of an inactive state during which user data regarding the mobile terminal 200 is neither transmitted nor received. The UE inactivity timer 105 is (re)started by the base station 100 and is used to determine the transition of the mobile terminal 200 from the CONNECTED state to the IDLE state. The UE inactivity timer 105 may be provided for each mobile terminal or for each terminal group. The terminal group may be defined, for example, by a unit of a terminal type, a unit of a service used by the mobile terminal 200, or a unit of a Quality of Service (QoS) class requested by the mobile terminal 200.
For example, the base station 100 (re)starts the UE inactivity timer 105 for the mobile terminal 200 when downlink or uplink radio resources are scheduled to the mobile terminal 200. Further or alternatively, the base station 100 may (re)start the UE inactivity timer 105 for the mobile terminal 200 in response to at least one of reception of downlink data for the mobile terminal 200, transmission of an uplink transmission grant (Uplink Grant) to the mobile terminal 200, transmission of a paging message to the mobile terminal 200, and reception of a radio resource allocation request from the mobile terminal 200. When the UE inactivity timer 105 expires, the mobile terminal 200 makes a transition from the CONNECTED state to the IDLE state.
The functions of the RAN terminal information acquisition unit 102, the RAN terminal information management unit 103, the configuration unit 104 and the like shown in
These programs can be stored and provided to a computer using any type of non-transitory computer readable media. Non-transitory computer readable media include any type of tangible storage media. Examples of non-transitory computer readable media include magnetic storage media (such as flexible disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g., magneto-optical disks), Read Only Memory (CD-ROM), CD-R, CD-R/W, and semiconductor memories (such as mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, random access memory (RAM), etc.). The program may be provided to a computer using any type of transitory computer readable media. Examples of transitory computer readable media include electric signals, optical signals, and electromagnetic waves. Transitory computer readable media can provide the program to a computer via a wired communication line (e.g., electric wires, and optical fibers) or a wireless communication line.
As already stated above, in the case of the UMTS, the base station 100 shown in
As described above, the base station 100 according to this embodiment is configured to save, in the MCN 30, the RAN terminal information (e.g., measurement information or history information) obtained in the RAN 20. Further, the base station 100 is configured to read out, from the MCN 30, the RAN terminal information, which has been saved in the MCN 30. Accordingly, even when the RAN terminal information has been released (deleted) in the RAN 20 according to the transition of the mobile terminal 200 to the IDLE state, the base station 100 can read out and use the RAN terminal information saved in the MCN 30 for the following settings of the mobile terminal 200. In other words, the base station 100 can continuously use the RAN terminal information for a time period over a plurality of CONNECTED-IDLE transitions of the mobile terminal 200. Accordingly, the base station 100 can perform a setting regarding the mobile terminal 200 (e.g., a setting of a timer value of an UE INACTIVITY TIMER) in consideration of the long-term RAN terminal information regarding the mobile terminal 200.
In this embodiment, an example in which the RAN terminal information is stored in the subscriber server 320 will be described. A configuration example of a mobile communication system according to this embodiment may be similar to that in
The subscriber server 320 may receive the RAN terminal information when a location update of the mobile terminal 200 is performed.
Next, an operation for reading out the RAN terminal information saved in the subscriber server 320 to the base station 100 will be described.
When the mobile terminal 200 moves across location registration areas, the subscriber server 320 may send the RAN terminal information to the mobility management node 300 that manages a new location registration area.
According to this embodiment, the subscriber server 320 is able to store the RAN terminal information. When the RAN terminal information is passed between different mobile operators, for example, the subscriber server 320 may store and manage the RAN terminal information.
In this embodiment, a transfer of the RAN terminal information between two mobility management nodes 300 will be described. A configuration example of a mobile communication system according to this embodiment may be similar to that in
The mobility management node 300 according to this embodiment may send the RAN terminal information to another mobility management node in response to an inter-cell movement (i.e., cell re-selection) of the mobile terminal 200 in the IDLE state. Specifically, the mobility management node 300 may send the RAN terminal information to another mobility management node when the mobile terminal 200 in the IDLE state has moved to a cell (base station) belonging to another mobility management node and have sent a location update request to another mobility management node.
Further, the mobility management node 300 according to this embodiment may send the RAN terminal information to another mobility management node in response to an inter-cell movement (i.e., handover) of the mobile terminal 200 in the CONNECTED state. Specifically, the mobility management node 300 may send the RAN terminal information to another mobility management node in response to a handover of the mobile terminal 200 in the CONNECTED state to a cell (base station) belonging to another mobility management node.
The sequences regarding the transfer of the RAN terminal information between the mobility management nodes 300 shown in
According to this embodiment, the RAN terminal information can be transferred between the mobility management nodes 300. Accordingly, in this embodiment, the RAN terminal information can be shared or re-used between the base stations 100 managed by different mobility management nodes.
In this embodiment, an example in which the RAN terminal information is transferred between the base stations 100 will be described. The transfer of the RAN terminal information between the base stations 100 described in this embodiment may be performed in addition to the operations for saving the RAN terminal information in the MCN 30 and reading out the RAN terminal information from the MCN 30 described in the above first to third embodiments. A configuration example of a mobile communication system according to this embodiment may be similar to that in
The base station 100 according to this embodiment may send the RAN terminal information to another base station in response to an inter-cell movement (i.e., handover) of the mobile terminal 200 in the CONNECTED state. Specifically, the base station 100 may send the RAN terminal information to another base station in response to a handover of the mobile terminal 200 in the CONNECTED state to a cell belonging to another base station.
The sequence regarding the transfer of the RAN terminal information between the base stations 100 shown in
According to this embodiment, the RAN terminal information can be transferred between the base stations 100. Accordingly, in this embodiment, the RAN terminal information acquired in any base station 100 can be directly transmitted to another base station 100 without passing through the MCN 30, and the RAN terminal information can be shared or reused between the base stations 100.
The first to fourth embodiments stated above may be appropriately combined.
Further, in the above first to fourth embodiments, a number of examples in which the base station 100 saves the RAN terminal information in the MCN 30 and reads out the RAN terminal information from the MCN 30 have been described. However, the operations for saving and reading out the RAN terminal information may be performed by a node in the RAN 20 other than the base station 100. Further, in the first to fourth embodiments, examples in which the management entity of the RAN terminal information in the MCN 30 is the mobility management node 300 or the subscriber server 320 have been shown. However, the management of the RAN terminal information in the MCN 30 may be performed by a node in the MCN 30 other than the mobility management node 300 or the subscriber server 320.
Further, in the above first to fourth embodiments, the specific example regarding the EPS has been mainly described. However, the mobile communication system according to the first to fourth embodiments may be another mobile communication system including a GPRS system. In the case of the GPRS system, a TAU REQUEST may be replaced by a RAU REQUEST, an S1AP message may be replaced by a Radio Access Network Application Part (RANAP) message, and a GUMMEI may be replaced by a Packet Temporary Mobile Subscriber Identity (P-TMSI).
Further, in the aforementioned operations, the RAN terminal information may be used even after the movement of the mobile terminal 200 across different access systems (e.g., a movement of the mobile terminal 200 from the UTRAN to the E-UTRAN). For example, the base station 100 or an RNC of the UTRAN may save the RAN terminal information acquired by the UTRAN in the MCN 30 (in this example, a GPRS packet core and an EPC). The base station 100 of the E-UTRAN may read out from the MCN 30 the RAN terminal information acquired by the UTRAN and use it.
Further, the above embodiments are merely examples regarding application of technical ideas obtained by the present inventors. The technical ideas are not limited to the embodiments stated above and may be changed in various ways.
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-222011, filed on Oct. 4, 2012, the disclosure of which is incorporated herein in its entirety by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-222011 | Oct 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/005582 | 9/20/2013 | WO | 00 |
