Wireless terminal and control program

Abstract

To easily and accurately notify the user of a wireless terminal that handover is not possible.SOLUTION: A wireless terminal 20 of the invention of the present application notifies a user of the wireless terminal 20 that handover to a new wireless base station 10 is not possible in a form different from a form of notifying the user of being out of a communication range of the wireless base station 10, if the new wireless base station 10 notifies the wireless terminal that handover is not possible, when handover processing is performed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless terminal that, when a handover is not possible, notifies a user of the wireless terminal that handover is not possible. [Background technology]

[0002] Generally, in a wireless system consisting of multiple wireless base stations and wireless terminals, there is a mechanism in which, when a wireless terminal selects a new wireless base station with which it can communicate based on the received field strength of the wireless base station, it performs a handover to the new wireless base station.

[0003] For example, when a moving wireless terminal detects a decrease in the received field strength of the current source wireless base station, control information is exchanged between the wireless terminal and a new destination wireless base station that has a wireless area in the direction of the wireless terminal's movement, and the wireless terminal's connection destination is switched from the source wireless base station to the destination wireless base station, thereby significantly expanding the communication area of ​​the wireless terminal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-175697 Summary of the Invention [Problem to be solved by the invention]

[0005] In the wireless terminal described above, if the number of communication connections at the destination wireless base station at the time of handover has reached its upper limit and there are no available communication connections, or if the destination wireless base station has insufficient resources, such as insufficient wireless line capacity, the destination wireless base station determines that handover is not possible.

[0006] Therefore, if the wireless terminal moves further, the received field strength for the source wireless base station will further decrease, and the wireless terminal will move out of the communication range of the source wireless base station, and in some cases, wireless communication with the wireless terminal will be cut off. Therefore, it is necessary for the target wireless base station to notify the wireless terminal that handover is not possible.

[0007] Conventionally, an out-of-service notification technique has been proposed in which, when a wireless terminal goes out of the communication range of a wireless base station, the wireless base station issues an out-of-service warning to the wireless terminal, indicating that the wireless terminal will be out of communication range (see, for example, Patent Document 1). When this out-of-service notification technique is applied to a handover impossible notification, the wireless terminal is notified of the impossibility of handover as an out-of-service warning.

[0008] However, such conventional technology cannot accurately notify a handover failure, distinguishing it from an out-of-service state, and therefore has a problem in that the user of the wireless terminal cannot distinguish between an out-of-service alarm that warns the user that the wireless terminal is out of the intended communication range and an out-of-service alarm that notifies the user that the handover is not possible. For this reason, if the user mistakenly recognizes the out-of-service alarm that notifies the user that the handover is not possible as an out-of-service alarm indicating that the user is out of the intended communication range, for example, if the user quickly moves into the communication range of the target wireless base station, the wireless communication may be disconnected.

[0009] The present invention has been made to solve the above problems, and has as its object to provide a wireless terminal that can easily and accurately notify the user of the wireless terminal that handover is not possible. [Means for solving the problem]

[0010] In order to achieve this object, a radio terminal according to the present invention is a radio terminal used in a radio system having a plurality of radio base stations and a plurality of radio terminals, and comprises: a control unit that performs handover processing to a second radio base station different from a first radio base station with which the radio terminal is currently communicating, based on a connection status with the first radio base station; and a notification unit that notifies a user of the radio terminal of the connection status with the radio base station based on an instruction from the control unit; when performing the handover processing, if the control unit receives a handover response from the second radio base station indicating that handover is not possible, the control unit transmits to the notification unit that handover to the second radio base station is not possible, and the notification unit notifies the user of the radio terminal that handover to the second radio base station is not possible in a second manner different from a first manner that notifies that the radio terminal is out of the communication range of the radio base station.

[0011] In addition, one configuration example of the wireless terminal according to the present invention is characterized in that the first form and the second form are at least either an audible form or a visible form.

[0012] Furthermore, one configuration example of the wireless terminal according to the present invention is characterized in that the handover response indicating that the handover is not possible includes a reason why the handover is not possible, the control unit notifies the notification unit of the reason why the handover is not possible, and the notification unit switches the notification form of the second form depending on the reason why the handover is not possible.

[0013] In order to achieve this object, the control program of the present invention is a control program for causing a computer to function as the wireless terminal used in a wireless system having a plurality of wireless base stations and a plurality of wireless terminals, wherein the wireless terminal comprises: a control unit that performs handover processing to a second wireless base station different from a first wireless base station based on a connection status with the first wireless base station with which the wireless terminal is communicating; and a notification unit that notifies a user of the wireless terminal of the connection status with the wireless base station based on an instruction from the control unit, and is characterized in that the control unit, when receiving a handover response from the second wireless base station indicating that handover is not possible when performing the handover processing, executes a step of transmitting to the notification unit that handover to the second wireless base station is not possible, and executes a step of notifying the user of the wireless terminal that handover to the second wireless base station is not possible in a second manner different from a first manner notifying that the wireless terminal is out of the communication range of the wireless base station. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a wireless terminal that easily and accurately notifies the user of the wireless terminal that handover is not possible. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram showing the configuration of a wireless system. [Figure 2] FIG. 2 is a diagram for explaining the movement of a wireless terminal in a wireless system. [Figure 3] FIG. 3 is a sequence diagram showing an alarm display operation when a wireless terminal moves out of the communication range. [Figure 4] FIG. 4 is a sequence diagram showing a handover impossibility notification operation when a wireless terminal performs a handover. DETAILED DESCRIPTION OF THE INVENTION

[0016] Next, an embodiment of the present invention will be described with reference to the drawings. [Radio System] First, a wireless system 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the wireless system.

[0017] The wireless system 1 is a wireless communication system mainly comprising wireless base stations 10 (10A, 10B, 10C) and wireless terminals 20 (20A, 20B, 20C), in which the wireless base stations 10 relay data communications such as voice calls of the wireless terminals 20 that use a communication network NW. The counterpart device 50 is a general communication device that is connected to the communication network NW and serves as a communication partner of the wireless terminals 20. The communication network NW is made up of known communication networks such as an IP communication network typified by the Internet and a mobile communication network.

[0018] The wireless base stations 10 are connected to a communication monitoring device 30 via a wired communication line L. The communication monitoring device 30 is a device that can monitor the connection status, communication status, and other operating conditions of the wireless terminals 20 at each wireless base station 10. For example, it can monitor the number of communication connections of the wireless terminals 20 at each wireless base station 10, resource usage such as wireless line capacity, and the like. The communication monitoring device 30 may be configured to be connected to each wireless base station 10 via a communication network NW.

[0019] In the following, an example will be described in which the wireless system 1 is configured with three wireless base stations 10 and three wireless terminals 20, but the present invention is not limited to this. The present invention can be applied to a case in which two or more wireless base stations 10 are provided and the wireless system 1 is configured with a plurality of wireless terminals 20 connectable to these wireless base stations 10, and similar actions and effects can be obtained.

[0020] [Radio base station] The wireless base station 10 (10A, 10B, 10C) includes a call control unit 11 that performs call control for the wireless terminal 20. The call control unit 11 can be configured by a computer including a CPU, a storage unit, an I / F unit, etc. (not shown), and can realize various functions in call control by causing the CPU to execute a control program stored in the storage unit.

[0021] [Call Control Unit] The call control unit 11 is configured to connect the wireless terminal 20 within its own resource range in response to a connection request from the wireless terminal 20, connect to the wireless terminal 20 via a wireless line, and relay and transfer the data communication of the wireless terminal 20 to the communication network NW via the communication line L.

[0022] The call control unit 11 is configured to check the latest resource usage, such as the number of its own communication connections and wireless line capacity, in response to a handover request from the wireless terminal 20. The number of wireless terminals 20 that are allowed to connect is limited by the upper limit of the number of communication connections and the resource usage, such as wireless line capacity. If there are available resources to allow an additional wireless terminal 20 to connect, the call control unit 11 is configured to return a handover response indicating that the connection is permitted and establish a new connection with the wireless terminal 20, whereas if there are insufficient resources and the additional wireless terminal 20 cannot be connected, the call control unit 11 is configured to return a handover response indicating that the connection is not permitted.

[0023] [Wireless terminal] The wireless terminal 20 (20A, 20B, 20C) includes a control unit 21 (21A, 21B, 21C) that controls the operation of the wireless terminal 20, and a notification unit 22 (22A, 22B, 22C) that provides various notifications to the user of the wireless terminal 20 in response to instructions from the control unit 21. The control unit 21 (21A, 21B, 21C) can be configured by a computer that includes a CPU, a storage unit, an I / F unit, etc. (not shown), and various functions of the wireless terminal can be realized by causing the CPU to execute a control program stored in the storage unit.

[0024] [Control Unit] The control unit 21 (21A, 21B, 21C) monitors the received field strength of the radio signal transmitted by each radio base station 10, and connects a radio line to a radio base station 10 with which good communication is possible. When a user operates the radio terminal 20 to instruct the start of communication, the radio terminal 20 is configured to connect to the communication network NW via the radio line and the radio base station 10.

[0025] The control unit 21 (21A, 21B, 21C) is configured to notify the notification unit 22 (22A, 22B, 22C) that the wireless terminal 20 is out of the communication range when the reception field strength received from the wireless base station 10 falls below a preset threshold level and communication is determined to be impossible. The user of the wireless terminal 20 can recognize that the wireless terminal 20 is out of the communication range by the out-of-range notification from the notification unit 22.

[0026] The control unit 21 (21A, 21B, 21C) is configured to perform handover processing to switch the connection to another wireless base station 10 (second wireless base station) so as to maintain communication when it is determined that communication with the wireless base station 10 (first wireless base station) currently in communication is poor.

[0027] In the handover process, a new wireless base station 10 with which communication is possible is selected according to the received field strength of the wireless signal transmitted by each wireless base station 10, a handover request is transmitted to the new wireless base station 10, and when a handover response indicating connection permission is notified from the new wireless base station 10 in response to the handover request, the wireless connection destination is switched from the currently connected wireless base station 10 to the new wireless base station 10.

[0028] On the other hand, when a handover response indicating that connection is not possible is notified from the new wireless base station 10 during handover processing to the new wireless base station 10, the control unit 21 (21A, 21B, 21C) is configured not to switch the wireless connection destination, but to notify the notification unit 22 (22A, 22B, 22C) that handover to the new wireless base station 10 is not possible.

[0029] [Notification Department] The notification unit 22 (22A, 22B, 22C) is composed of an audible device and a visual device, and is configured to notify the user of the wireless terminal 20 in an audible or visual form of information related to call control, information related to the operating state such as the connection state and communication state with the wireless base station, information related to user operations, etc., in response to instructions from the control unit 21. The audible device is composed of a sound source and a speaker, and the visual device can be composed of a visual display device such as an LCD or LED.

[0030] The notification unit 22 (22A, 22B, 22C) is configured to use either an audible device or a visual device, or both, to notify that the wireless terminal 20 has gone out of the communication range or that handover to a new wireless base station 10 is not possible. Here, the notification unit 22 (22A, 22B, 22C) of the present embodiment is configured to notify that handover is not possible in a form (second form) different from the form (first form) of notifying that the wireless terminal 20 has gone out of the communication range.

[0031] For example, when an audible device notifies the user that the user is out of communication range and that handover is not possible, the notification may be made using different sounds. Furthermore, when a visual device notifies the user of this information, the notification may be made using different display formats, such as different display designs, colors, or lighting / flashing methods. By notifying the user that handover is not possible in a format (second format) different from the format (first format) for notifying the user that the user is out of communication range, the user can easily distinguish between the fact that the user is out of communication range and the fact that handover to a wireless base station is not possible.

[0032] Furthermore, the notification unit 22 (22A, 22B, 22C) may switch the form of notification to the user depending on the reason why handover is not possible, notified by the communication monitoring device 30. This allows the user of the wireless terminal to recognize the reason why handover is not possible, and therefore, when handover is not possible, the user can be assisted in selecting various actions depending on the reason why handover is not possible.

[0033] [Operation of this embodiment] Next, the operation of the wireless system 1 according to this embodiment will be described with reference to Fig. 2 to Fig. 4. Fig. 2 is a diagram for explaining movement of a wireless terminal in the wireless system. Fig. 3 is a sequence diagram showing an alarm display operation when a wireless terminal moves out of communication range. Fig. 4 is a sequence diagram showing a handover impossible notification operation when a wireless terminal is handed over.

[0034] [When moving outside of communication range] The alarm display operation when wireless terminal 20A moves out of the communication range will be described with reference to Figures 2 and 3. As shown in Figure 3, in an initial state, wireless terminal 20A, which is wirelessly connected to wireless base station 10A (first wireless base station) with good communication quality, is located at position P in Figure 2 and is performing data communication with counterpart device 50 via wireless base station 10A (step 100).

[0035] Here, if the wireless terminal 20A moves from position P toward position Q and goes outside the wireless area ZA of the wireless base station 10A (step 101), the received field strength for the wireless base station 10A decreases and the communication quality becomes poor (step 102).

[0036] The wireless terminal 20A checks the wireless base station 10 to be the handover destination based on the received field strength detected from the wireless base stations 10 other than the wireless base station 10A. If there is no wireless base station 10 that can be wirelessly connected with good communication quality and the handover destination cannot be found (step 103), the handover becomes impossible and the state of the above-mentioned step 102 is maintained.

[0037] Thereafter, if the poor communication quality state of step 102 continues, and if wireless terminal 20A moves further and the communication quality further deteriorates, wireless terminal 20A determines that it is out of communication range (step 104) and issues an out-of-communication range alarm in a predetermined format (first format) (step 105). This notifies the user of wireless terminal 20A that it has moved out of the wireless area ZA of wireless base station 10A.

[0038] [During handover] 2 and 4, the operation of displaying that handover is not possible during handover of the wireless terminal 20A will be described.

[0039] As shown in Fig. 4, in an initial state, it is assumed that wireless terminal 20A, which is wirelessly connected to wireless base station 10A (first wireless base station) with good communication quality, is located at position P in Fig. 2 and is performing data communication with counterpart device 50 via wireless base station 10A (step 110). If wireless terminal 20A moves from position P toward position R and moves out of wireless area ZA of wireless base station 10A (step 111), the received field strength for wireless base station 10A decreases, causing communication quality to deteriorate (step 112).

[0040] The wireless terminal 20A selects a wireless base station 10 as a handover destination based on the received field strength detected from wireless base stations 10 other than the wireless base station 10A. If a wireless base station 10B (second wireless base station) that can be wirelessly connected with good communication quality is present and a handover destination is found (step 113), the wireless terminal 20A transmits a handover request to the wireless base station 10B (step 114).

[0041] In response to the handover request from the wireless terminal 20A, the wireless base station 10B checks its own latest resource usage amount. If there are available resources, the wireless base station 10B returns a handover response indicating connection permission to the wireless terminal 20A (step 115).

[0042] When the wireless terminal 20A receives a handover response indicating permission for connection from the wireless base station 10B in response to the handover request, the wireless terminal 20A performs handover processing by switching the wireless connection destination from the wireless base station 10A to the wireless base station 10B. This allows data communication with the counterpart device 50 to continue with good communication quality via the wireless base station 10B.

[0043] On the other hand, if there are no available resources, the radio base station 10B returns a handover response indicating that connection is not possible to the radio terminal 20A (step 120). This handover response indicating that connection is not possible may include the reason for the connection being not possible. For example, as shown in Fig. 2, if two radio terminals 20B and 20C are connected to the radio base station 10B, the number of communication connections is two, and the upper limit (maximum number of connections) is two, the radio base station 10B determines that it is not possible to connect an additional radio terminal 20, and transmits a handover response indicating that connection is not possible, including information that the number of connections is at the upper limit.

[0044] When wireless terminal 20A receives a handover response indicating that connection is not possible from wireless base station 10B in response to the handover request, wireless terminal 20A notifies that handover is not possible using notification unit 22 in a manner (second manner) different from the manner (first manner) for notifying the out-of-service warning in Fig. 3 (step 121). This allows the user of wireless terminal 20A to recognize that handover is not possible, distinguishing this from a normal out-of-service warning.

[0045] In this way, the user of wireless terminal 20A can be easily and accurately notified that handover is not possible, and the user can easily and accurately recognize that handover is not possible by distinguishing it from a normal out-of-service area warning. When handover is not possible, the user of wireless terminal 20A can recognize that handover is not possible even if the user continues moving in the direction of new wireless base station 10B, and can therefore select an appropriate action to take when handover is not possible, such as returning in the direction of the original wireless base station 10A. If such a selection is made, it is possible to avoid the user of wireless terminal 20A from disconnecting communication with the remote device.

[0046] Furthermore, when the wireless terminal 20A is notified of the reason why handover is not possible from the wireless base station 10B, such as that the number of communication connections at the wireless base station 10B has reached its upper limit or that the capacity of the wireless line has reached its upper limit, the wireless terminal 20A may switch the notification format of the handover not possible notification depending on the reason. This allows the user to understand the reason why handover is not possible, and accordingly, it becomes possible to select more appropriate actions, such as avoiding congested wireless areas.

[0047] [Advantages of this embodiment] In this way, in this embodiment, when the control unit 21 of the wireless terminal 20 is notified by the new wireless base station 10 that handover is not possible during handover processing, the control unit 21 notifies the notification unit 22 that handover to the new wireless base station 10 is not possible in a notification format different from the out-of-service area warning notification indicating that the wireless terminal is out of service area.

[0048] This allows the user of the wireless terminal to be easily and accurately notified that handover is not possible, and the user of the wireless terminal can easily and accurately recognize that handover is not possible by distinguishing it from an out-of-service warning. Therefore, the user can recognize that if handover is not possible, handover will not be possible even if the user continues moving in the direction of a new wireless base station 10, and can select an appropriate action to take when handover is not possible, such as returning in the direction of the original wireless base station 10. The present invention is extremely effective in avoiding disconnection of data communication during handover, and is extremely suitable for real-time communication, such as voice communication or video communication using RTP (Real-time Transport Protocol), in which communication disconnection significantly deteriorates quality.

[0049] Furthermore, when the wireless base station 10 notifies the wireless terminal 20 of the reason why handover is not possible, such as that the number of communication connections at the wireless base station 10 has reached its upper limit or that the capacity of the wireless line has reached its upper limit, the wireless terminal 20 may switch the form of the notification of handover not possible depending on the reason. This allows the user to understand the reason why handover is not possible, and accordingly, it becomes possible to select more appropriate actions, such as avoiding congested wireless areas.

[0050] [Extended embodiment] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. The embodiments of the present invention can be modified in various ways that are understandable to those skilled in the art within the scope of the present invention.

[0051] In the above-described embodiment, the wireless system 1 is described as being configured from the wireless base station 10 and the wireless terminal 20, but the present invention is not limited to this. For example, the wireless base station 10 and the wireless terminal 20 may be configured from a base station and multiple handset terminals capable of handover in a system using cordless telephone devices. The present invention can also be applied to a wireless system in which handset terminals are relayed and connected to a general telephone network such as an IP telephone network, thereby realizing a wireless system that achieves the same effects as the present invention. [Explanation of symbols]

[0052] 1...wireless system, 10, 10A, 10B, 10C...wireless base station, 11...call control unit, 20, 20A, 20B, 20C...wireless terminal, 21A, 21B, 21C...control unit, 22A, 22B, 22C...notification unit, 30...communication monitoring device, 50...other device, L...communication line, NW...communication network, ZA, ZB...wireless area.

Claims

1. The wireless terminal is used in a wireless system including a plurality of wireless base stations and a plurality of wireless terminals, a control unit that performs handover processing to a second radio base station different from the first radio base station based on a connection state with the first radio base station in communication; a notification unit that notifies a user of the wireless terminal of a connection state with the wireless base station based on an instruction from the control unit, when performing the handover process, if a handover response indicating that handover is not possible is notified from the second radio base station, the control unit transmits to the notification unit information that handover to the second radio base station is not possible; the notification unit notifies the user of the wireless terminal that handover to the second wireless base station is not possible in a second manner different from a first manner for notifying that the wireless terminal is out of the communication range of the wireless base station; the handover response indicating that the handover is not possible includes a reason why the handover is not possible; The control unit notifies the notification unit of a reason why the handover is not possible, and the notification unit switches the notification form of the second form according to the reason why the handover is not possible. A wireless terminal characterized by:

2. The first form and the second form are at least one of an audible form and a visible form.

2. The wireless terminal according to claim 1, wherein:

3. A control program for causing a computer to function as a wireless terminal used in a wireless system including a plurality of wireless base stations and a plurality of wireless terminals, the control program comprising: the wireless terminal comprises: a control unit that performs handover processing to a second wireless base station different from the first wireless base station based on a connection state with the first wireless base station currently in communication; and a notification unit that notifies a user of the wireless terminal of the connection state with the wireless base station based on an instruction from the control unit; causing the control unit to execute a step of transmitting to the notification unit, when a handover response indicating that handover is not possible is notified from the second radio base station when performing the handover process, the notification unit indicating that handover to the second radio base station is not possible; causing the notification unit to notify a user of the wireless terminal that handover to the second wireless base station is not possible in a second manner different from a first manner for notifying that the wireless terminal is out of the communication range of the wireless base station; the handover response indicating that the handover is not possible includes a reason why the handover is not possible; causing the control unit to notify the notification unit of a reason why the handover is not possible, and causing the notification unit to switch the notification form of the second form according to the reason why the handover is not possible. A control program characterized by:

Images