JP2011135470A - Terminal, and mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a terminal from automatically connecting to any other base station in the case where the terminal is located in an overlapping part of areas managed by a plurality of base stations and a connection is rejected from a base station desired to connect. <P>SOLUTION: In the case where a connection rejection is received from a femtocell base station 21 that is a base station desired to connect, a terminal 35 inquires the possibility of a connection to a macrocell base station 23, that is another base station, of a user via a user interface section 36. When a rejection of the connection to the other base station is inputted from the user, without transmitting a connection request to the macrocell base station 23, after the lapse of a fixed time, the terminal 35 transmits the connection request to the femtocell base station 21 again. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to control when a terminal is connected to a base station in a mobile communication system.

  In a mobile communication system, a plurality of base stations have jurisdiction over their respective areas (cells), but there are overlapping portions in the areas. In a conventional mobile communication system, when a terminal is located in an overlapping portion of an area controlled by a plurality of base stations, a mechanism for determining which base station and a radio link should be established based on the state of the terminal It has become.

  Recently, femtocells are coexisting with conventional macrocells. The femtocell is aimed at complementing local radio dead zones. A control method has been proposed in which a terminal registered in a femtocell base station is preferentially connected to the femtocell base station. In addition, use of the femtocell for the purpose of providing a predetermined service is also under consideration.

  In the future, by connecting from the terminal to the femtocell base station, it is conceivable that a special service is provided to the user, for example, a service in which a call charge is discounted when talking on the femtocell. When such a service is provided, the user expects a connection to the femtocell base station. However, femtocell base stations are limited in terms of performance in order to achieve miniaturization, and have a small capacity for simultaneous connection. For this reason, in the femtocell, a situation in which a new call connection request is rejected due to excess of the simultaneous connectable capacity is likely to occur.

  For example, in TS25.311 of the 3GPP standard, it is defined that when an RRC Connection Reject is received, if there is another connectable base station, connection to the base station is attempted. In the conventional mobile communication system, even if a terminal exists in the area (ie, femtocell) that the femtocell base station has jurisdiction according to the current 3GPP standard, it can be connected to the femtocell base station due to excess simultaneous connectable capacity. If not, control is performed to automatically connect to the macro cell base station (see, for example, Patent Document 1).

JP2008-278263

3GPP standard TS25.331

  In the conventional mobile communication system, when the capacity of the femtocell base station that can be connected simultaneously is exceeded, the connection from the terminal to the femtocell base station is rejected, and the control automatically connects to the macrocell base station. . Therefore, there is a problem that the terminal arbitrarily connects to the macro cell base station, contrary to the intention of the user who expects to enjoy a special service by connecting to the femto cell base station. Satisfy user's request to establish connection with femtocell base station after waiting for connection to femtocell base station without connecting to macrocell base station to enjoy expected service Can not do it.

  The present invention has been made in order to solve the above-described problems. When a connection to a base station to which connection is desired is rejected, automatic transmission to another base station contrary to the user's intention is performed. The purpose is to prevent connection.

  When the control unit determines that the terminal according to the present invention has refused connection from the first base station (femtocell base station), the user can connect to the second base station (macrocell base station). Is provided with a user interface unit for inquiring.

  In the present invention, when the connection is rejected from the femtocell base station, the user is automatically connected to the base station contrary to the user's intention in order to inquire whether the user can connect to the macrocell base station via the user interface unit. Can be prevented.

It is a state transition diagram which shows the connection procedure of the terminal in Embodiment 1 of this invention. 1 is a configuration diagram showing a mobile communication system in a first embodiment of the present invention. It is a block diagram which shows the structure of the terminal in Embodiment 1 of this invention. It is a sequence diagram which shows operation | movement of the mobile communication system in Embodiment 1 of this invention. It is a sequence diagram which shows operation | movement of the mobile communication system in Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the terminal in Embodiment 1 of this invention. It is a state transition diagram which shows the connection procedure of the terminal in Embodiment 2 of this invention. It is a sequence diagram which shows operation | movement of the mobile communication system in Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the terminal in Embodiment 2 of this invention.

  A mobile communication system and a terminal according to the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals indicate the same or corresponding configurations. In addition, this invention is not limited to each embodiment shown below.

Embodiment 1 FIG.
FIG. 1 is a state transition diagram showing a terminal connection procedure according to Embodiment 1 of the present invention. The state of the terminal in the connection stage to the base station includes an initial state 10, a connection response waiting state 12, a user response waiting state 14, a connection response waiting state (retrying) 15, another cell connection sequence state 16, a connection establishment state 50. There is. First, the terminal is in the initial state 10 when it is activated. The terminal in the initial state 10 transmits a connection request to the base station to which it wants to connect, and transitions to a connection response waiting state 12, triggered by the user performing a call operation. A terminal in the connection response waiting state 12 enters a connection establishment state 50 when receiving a connection permission from a base station that it desires to connect to. On the other hand, if the terminal in the connection response waiting state 12 receives a connection refusal from the base station that it wants to connect to, the terminal determines whether there is another base station that can be connected (the presence or absence of other cells). The transition destination is different.

  When there is another base station that can be connected (when there is another cell), the terminal that has received the connection refusal in the connection response waiting state 12 inquires the user whether the connection to the other base station is possible. The answer waiting state 14 is entered. For example, a method for inquiring whether or not a user can connect is provided with a user interface unit in a terminal, and outputs a message to the user interface unit as to whether or not connection to another base station is inquired. On the other hand, it is only necessary to input connection possibility. On the other hand, if there is no other base station that can be connected in the connection response waiting state 12 when there is no other base station that can be connected (when there is no other cell), The connection request is transmitted again, and the connection response waiting state (retrying) 15 is entered.

  When the terminal in the user response waiting state 14 obtains an answer from the user that refuses connection to another base station, after a certain time has elapsed, it transmits a connection request to the base station that initially requested connection, and waits for a connection response. State (retrying) 15 is entered. When the terminal in the user answer waiting state 14 obtains an answer permitting connection to another base station from the user, it transmits a connection request to another connectable base station, and shifts to another cell connection sequence state 16.

  When a terminal in the connection response waiting state (retrying) 15 receives a connection refusal from a base station that desires connection, it transmits a connection request to the base station that desires connection after a certain period of time and waits for a connection response again. State (retrying) 15 is entered. Further, when a terminal in the connection response waiting state (retrying) 15 receives a connection permission from a base station that desires connection, the terminal enters a connection establishment state 50.

  FIG. 2 is a configuration diagram showing the mobile communication system according to Embodiment 1 of the present invention. As a plurality of overlapping areas, the femtocell 22 and the macrocell 24 coexist. A femtocell base station 21 that is a first base station has jurisdiction over a femtocell 22 that is a local cell, and a macrocell base station 23 that is a second base station has jurisdiction over a macrocell 24 that is a wide-area cell. . FIG. 2 shows a case where the entire femtocell 22 and a part of the macrocell 24 overlap. Note that the first base station and the second base station have different types of base stations, such as femtocell base stations and macrocell base stations, and are prioritized for connection at the terminal. To do.

  In the femtocell base station 21, terminals that can be connected to the own station are registered in advance. A terminal registered in advance in the femtocell base station 21 can enjoy a special service by connecting to the femtocell base station 21. The terminal registered in the femtocell base station 21 is associated with the femtocell base station 21 and has selected the femtocell base station 21 as a base station desired to be connected. That is, it is set in the terminal that the femtocell base station 21 has a higher connection priority than the macrocell base station 23.

  In FIG. 2, the terminal 25 is located in the femtocell 22 and has established a connection with the femtocell base station 21. The terminal 35 is located in the femtocell 22 but is not yet connected to the femtocell base station 21. The femtocell base station 21 has established connections with the same number of terminals as the simultaneously connectable capacity, and it is impossible to connect with more terminals. However, the terminal 35 is trying to establish a new connection to the femtocell base station 21. The terminal 35 is registered in advance in the femtocell base station 21, and the connection priority is higher in the femtocell base station 21 than in the macrocell base station 23. Since the terminal 35 can enjoy a special service when connected to the femtocell base station 21, the terminal 35 selects the femtocell base station 21 in advance as a base station that desires connection.

  FIG. 3 is a block diagram showing a configuration of terminal 35 in Embodiment 1 of the present invention. The terminal 35 includes a user interface unit 36 that inputs and outputs data with a user, and a control unit 37 that controls wireless communication with the base station.

  FIG. 4 is a sequence diagram showing an operation of the mobile communication system in the first embodiment of the present invention. FIG. 4 shows the operation of the mobile communication system until the terminal 35 transitions from the initial state 10 to the other cell connection sequence state 16 and receives connection permission from the base station (macrocell base station 23) of the other cell. .

  When the user performs a call operation on the terminal 35, the terminal 35 in the initial state 10 transmits a connection request to the base station (femtocell base station 21) having the highest connection priority, and enters the connection response waiting state 12. . The terminal 35 that has received the connection refusal from the femtocell base station 21 outputs a content for inquiring whether or not to connect to another base station from the control unit 37 to the user interface unit 36 (confirmation of other cell connection). The answer waiting state 14 is entered. When the user interface unit 36 inputs to the control unit 37 the content for permitting connection to another base station, the terminal 35 issues a connection request to another connectable base station, that is, the macrocell base station 23. Transmit to another cell connection sequence state 16. FIG. 4 shows an example in which connection permission is transmitted from the macrocell base station 23 to the terminal 35, and the terminal 35 has successfully connected to the macrocell base station 23.

  FIG. 5 is a sequence diagram showing an operation of the mobile communication system in the first embodiment of the present invention. FIG. 5 shows the movement from the initial state 10 until the terminal 35 transitions from the connection response waiting state 12, the user response waiting state 14, and the connection response waiting state (retrying) 15 to the connection establishment state 50. The operation | movement of a body communication system is shown. The operation of the mobile communication system until the terminal 35 transitions from the initial state 10 to the user response waiting state 14 is the same as that in FIG. Hereinafter, an operation after the terminal 35 confirms connection to another cell and enters the user answer waiting state 14 will be described.

  If there is an input from the user interface unit 36 to the control unit 37 that denies connection to another base station, the terminal 35 does not connect to the macrocell base station 23, and after a certain period of time has passed, the femtocell A connection request is transmitted to the base station 21, and a connection response waiting state (retrying) 15 is entered. When the connection rejection is received from the femtocell base station 21, the terminal 35 transmits a connection request to the femtocell base station 21 again after a certain period of time, and continues the connection response waiting state (during retry) 15. The terminal 35 that has received the connection permission from the femtocell base station 21 enters the connection establishment state 50.

  FIG. 6 is a flowchart showing the operation of the terminal 35 in the first embodiment of the present invention. When the terminal 35 in the initial state (step S10) confirms the call operation from the user (step S20), the terminal 35 transmits a connection request to the base station having the highest connection priority (step S30). In step S40, the terminal 35 determines whether or not the response from the base station that desires to connect permits the connection. If the response permits the connection, the terminal 35 establishes a connection with the base station. A state is reached (step S50). On the other hand, if the response from the base station does not permit connection, the terminal 35 proceeds to step S60.

  In step S60, the terminal 35 determines whether or not there is another connectable base station. If there is no other connectable base station, the terminal 35 proceeds to step S70 and a certain time elapses. After waiting, return to step S30. On the other hand, if there is another connectable base station, the terminal 35 inquires of the user whether or not the connection to the other base station is possible (step S80). Next, the terminal 35 determines whether or not the connection to the other base station is permitted by the user (step S90). If it is determined that the connection to the other base station is permitted, the other cell connection sequence is determined. Transition to the state (step S100). On the other hand, if it is determined that the connection to another base station has been rejected, the process returns to step S70.

  In the above description, the case where the terminal 35 is located in a portion where the femtocell 22 and the macrocell 24 overlap is described. That is, the terminal 35 is located in an overlapping portion of each area under the jurisdiction of different types of base stations, and the terminal 35 is not located in an overlapping portion of each area under the jurisdiction of the same type of base stations. . For example, when the terminal 35 is located in an overlapping portion of each area under the jurisdiction of a plurality of macro cell base stations, there is no difference in connection priority among the plurality of macro cell base stations. Even if connection refusal is received, the user is not inquired of whether or not to connect to another macro cell base station. The control unit 37 of the terminal 35 automatically determines which macro cell base station to connect to based on, for example, the received electric field strength from each macro cell base station. As described above, only when there is a difference in connection priority among a plurality of connectable base stations, the terminal 35 inquires the user whether or not connection to another base station is possible via the user interface unit 36. .

  In the first embodiment, when a connection is rejected by a base station (femtocell base station 21) that desires connection, the terminal 35 sends another base station (macrocell base station 23) to the user via the user interface unit 36. ) Can be prevented from being automatically connected to a base station contrary to the user's intention. The user can select connection change to the macro cell base station 23 when he / she wants to give priority to establishment of connection, and can maintain a connection request to the femto cell base station 21 when he / she wants to enjoy a special service.

Embodiment 2. FIG.
In the first embodiment, when there is a connection rejection response from the base station that desires connection, the terminal inquires whether the user can connect to another cell or not in the second embodiment. Do not do. In the second embodiment, whether to connect to another base station is set in advance in the terminal, and the control unit refers to the setting to determine the state transition. Interaction can be omitted. Note that the configuration of the mobile communication system is the same as that of the first embodiment, and a description thereof will be omitted. In the following, as in the first embodiment, the description will be made on the assumption that the femtocell base station 21 has a higher priority of connection from the terminal than the macrocell base station 23.

  FIG. 7 is a state transition diagram showing a terminal connection procedure according to Embodiment 2 of the present invention. The state of the terminal 35 in the connection stage to the base station includes an initial state 10, a connection response waiting state 12, a connection response waiting state (retrying) 15, another cell connection sequence state 16, and a connection establishment state 50. There is no answer waiting state.

  First, the terminal 35 is in the initial state 10 when it is activated. The terminal 35 in the initial state 10 transmits a connection request to the base station that it wants to connect to, as a trigger when the user performs a call operation, and enters the connection response waiting state 12. The terminal 35 in the connection response waiting state 12 enters the connection establishment state 50 when receiving a connection permission from the base station that it desires to connect to. On the other hand, if the terminal 35 in the connection response waiting state 12 receives a connection refusal from the base station that it wishes to connect to, it is determined whether there is another base station that can be connected or connection to another base station. The transition destination of the state is different based on the availability setting state.

  If there is another base station that can be connected and permission to connect to another base station is set in advance, the terminal 35 that has received the connection rejection in the connection response waiting state 12 A connection request is transmitted to the other cell connection sequence state 16. On the other hand, when there is no other base station that can be connected, or when connection refusal to another base station is preset, the terminal 35 that has received the connection refusal in the connection response waiting state 12 has passed for a certain period of time. Later, a connection request is transmitted again to the base station that desires connection, and a connection response waiting state (retrying) 15 is entered.

  When the terminal 35 in the connection response waiting state (retrying) 15 receives a connection refusal from the base station that desires connection, the terminal 35 transmits a connection request again to the base station that desires connection after a predetermined time has elapsed, and receives a connection response. The waiting state (retrying) 15 is maintained. When the terminal 35 in the connection response waiting state (retrying) 15 receives connection permission from the base station that desires connection, the terminal 35 enters the connection establishment state 50.

  FIG. 8 is a sequence diagram showing an operation of the mobile communication system in the second embodiment of the present invention. FIG. 8 shows an operation example in the case where the terminal 35 is previously set to allow or reject connection to other cells. When the user performs a call operation on the terminal 35, the terminal 35 in the initial state 10 transmits a connection request to the base station (femtocell base station 21) having the highest connection priority, and enters the connection response waiting state 12. . The terminal 35 that has received the connection refusal from the femtocell base station 21 refers to the connection permission / inhibition setting to another cell. Here, since the connection permission / inhibition setting to another cell is set to connection rejection, a connection request is transmitted to the femtocell base station 21 again after a predetermined time has elapsed, and the connection response waiting state (retrying) 15 is entered. . The terminal 35 that has received the connection permission from the femtocell base station 21 enters the connection establishment state 50.

  FIG. 9 is a flowchart showing the operation of the terminal 35 in the second embodiment of the present invention. When the terminal 35 in the initial state (step S10) confirms the call operation from the user (step S20), the terminal 35 transmits a connection request to the base station having the highest connection priority (step S30). In step S40, the terminal 35 determines whether or not the response from the base station that desires to connect permits the connection. If the response permits the connection, the terminal 35 establishes a connection with the base station. A state is reached (step S50). On the other hand, if the response from the base station does not permit connection, the terminal 35 proceeds to step S65.

  In step S65, the terminal 35 determines whether or not there is another base station that can be connected, and refers to the connection availability setting to another cell. If there is no other base station that can be connected, or the connection permission / non-connection setting to another cell is set to connection rejection, the process proceeds to step S70, and after waiting for a certain period of time, Return to S30. On the other hand, if there is another base station that can be connected and the connection permission / non-connection setting for other cells is set to connection permission, the state shifts to another cell connection sequence state (step S100).

  In the second embodiment, whether to connect to another base station is set in the terminal 35 in advance, and the control unit 37 refers to the setting to determine the state transition. The exchange regarding the cell connection confirmation can be omitted, and the operability of the terminal 35 is improved. Further, as in the first embodiment, it is possible to prevent automatic connection to a base station contrary to the user's intention.

21 Femtocell base station 22 Femtocell 23 Macrocell base station 24 Macrocell 35 Terminal 36 User interface unit 37 Control unit

Claims (5)

A control unit that transmits a connection request to the first base station having the highest connection priority, and determines whether or not to connect to the first base station based on a response from the first base station;
A user interface unit that inquires whether the user can connect to the second base station when the control unit determines that the connection is rejected from the first base station;
A terminal equipped with.   When the control unit receives a connection refusal to the second base station from the user via the user interface unit, the control unit again transmits the connection request to the first base station after a predetermined time has elapsed. The terminal according to claim 1, wherein: A control unit that transmits a connection request to the first base station having the highest connection priority, and determines whether or not to connect to the first base station based on a response from the first base station;
A user interface unit that presets whether or not to connect to a second base station that is a base station other than the first base station, with respect to the control unit;
If the connection to the second base station is set to be rejected, the control unit may determine that the connection has been rejected from the first base station even after a predetermined time has elapsed. A terminal that transmits the connection request to the base station again. In a mobile communication system comprising a first base station, a second base station, and a terminal,
The terminal is located in an overlapping portion of the area under the jurisdiction of the first base station and the second base station,
When it is set in the terminal that the first base station is higher in connection priority than the second base station,
The terminal transmits a connection request to the first base station based on a call origination operation from a user, and receives a connection refusal from the first base station as a response to the connection request. A mobile communication system for inquiring whether or not to connect to the second base station. In a mobile communication system comprising a first base station, a second base station, and a terminal,
The terminal is located in an overlapping portion of the area under the jurisdiction of the first base station and the second base station,
When the first base station has a higher connection priority than the second base station, and the terminal is set in advance to refuse connection to the second base station,
The terminal transmits a connection request to the first base station based on a call origination operation from a user, and receives a connection refusal from the first base station as a response to the connection request. A mobile communication system that transmits the connection request again to the first base station.

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