JP2014160892A - Mobile terminal, program and method for controlling reception buffer of data packet in area around communication quality deterioration area - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile terminal and the like that perform control such that they stock up on data packets in a reception buffer as many as possible when they enter a communication quality deterioration area without recognizing the travel path of the mobile terminal.SOLUTION: A mobile terminal includes: a radio communication unit for searching for peripheral base stations; and a reception buffer unit for temporarily buffering data packets received from a distribution server via a base station. In addition, the mobile terminal includes: peripheral base station storage means for pre-storing identifiers of peripheral base stations that can be searched for in a surrounding area of the communication quality deterioration area; base station determination means for determining whether or not the identifier of a peripheral base station which the radio communication unit searched for corresponds with the identifiers of the peripheral base stations stored in the peripheral base station storage means; and reception buffer control means for sending back a confirmation message to request reception of the next data packet to the distribution server in order to buffer data packets until the allowable value of the reception buffer unit as many as possible when the base station determination means determined true.

Description

  The present invention relates to a technique for receiving in advance necessary data before a mobile terminal shifts from an online state to an offline state.

  In recent years, with the development of wireless networks such as mobile phone networks, wireless local area networks (LANs), and WiMAX (Worldwide Interoperability for Microwave Access), mobile terminals are expanding the areas where online states can be maintained. On the other hand, when a user who possesses a portable terminal gets on a vehicle such as a train or an automobile, the portable terminal is forced to be in an offline state when the vehicle enters the underground or a tunnel.

  Conventionally, there is a technique in which a server predicts whether or not there is an offline area on a moving route of a client terminal by a communication prediction algorithm (see, for example, Patent Document 1). According to this technology, the client terminal can refer to the data even in the offline state by receiving in advance the necessary data before going into the offline state based on the prediction result. In addition, there is a technique in which a server transmits a position or time in an offline state and a position or time in an online state to the client terminal on the moving route of the client terminal (see, for example, Patent Document 2). According to this technique, the client terminal stops the communication function when it reaches the predicted position or time to be in the offline state. In addition, when the client terminal reaches the predicted position or time to be in the online state, the client terminal returns the communication function.

JP 2011-061713 A JP 2011-061714 A

  Smartphones are becoming popular as portable terminals. Unlike a conventional mobile phone, a smartphone is not limited to sending and receiving e-mails, and can receive website browsing and streaming services. That is, the user can receive these services using a smartphone even when the user is on the vehicle and moving. Specifically, the distribution server continuously distributes encoded data packets based on an application executed on a smartphone. On the other hand, the mobile terminal receives these data packets via the base station and temporarily stores them in the buffer. Then, the mobile terminal reproduces the data packet output from the buffer while decoding it.

  On the other hand, when a vehicle on which a user who has a smartphone has entered a basement or a tunnel, the vehicle enters an offline state at the same time, and these services are forcibly stopped. Of course, it is not limited to underground or tunnels, and the same applies when passing through a communication quality degraded area.

  FIG. 1 is a spatial external view showing movement of a mobile terminal.

  A mobile terminal (for example, a smartphone) 1 possessed by a user is under the control of a plurality of base stations 2 and continues to receive radio waves from the base stations. The mobile terminal 1 communicates with any one base station as a connection base station, and recognizes other base stations as adjacent base stations. Also, according to FIG. 1, the user is in a car and keeps moving. During this time, the mobile terminal 1 continues communication while switching the base station connected via the wireless link. An access network (for example, a mobile phone network) to which the base station 2 is connected is mutually connected to the Internet to which the distribution server 3 is connected. Therefore, the data packet transmitted from the distribution server 3 is transferred to the mobile terminal 1 via the base station 2 via the Internet.

  According to FIG. 1, the vehicle on which the user carrying the smartphone 1 is about to enter the tunnel. Further, it is assumed that the user is viewing, for example, a streaming service with the smartphone 1. If the vehicle enters the tunnel as it is, it enters an offline state, and the streaming service for the user is immediately stopped.

  Here, by using the techniques described in Patent Documents 1 and 2, data packets can be stored in the reception buffer as much as possible before going offline. Thereby, even if the portable terminal 1 shifts to the offline state, the data packets already accumulated in the reception buffer can be reproduced little by little.

  However, according to the techniques described in Patent Documents 1 and 2, the server needs to recognize in advance the movement path of the mobile terminal in order to use the communication prediction algorithm. Therefore, the mobile terminal needs to sequentially transmit the movement progress information to the server. Further, since the calculation amount of the communication prediction algorithm is large, it is not possible to predict the position or time of the offline state using only the mobile terminal. Therefore, the mobile terminal needs to receive the prediction result of the communication prediction algorithm from the server via the network.

  Therefore, the present invention provides a mobile terminal, a program, and a method for performing control so as to accumulate data packets in a reception buffer as much as possible when entering a communication quality degradation area without recognizing the movement route of the mobile terminal. With the goal.

According to the present invention,
A wireless communication unit that searches for a nearby base station and connects to the base station via a wireless link;
In a portable terminal having a reception buffer unit that temporarily buffers data packets received from a distribution server via a base station using a wireless communication unit,
Peripheral base station storage means for storing in advance an identifier of a searchable peripheral base station for the peripheral area of the communication quality degradation area;
Base station determination means for determining whether or not the identifier of the neighboring base station searched by the wireless communication unit matches the identifier of the neighboring base station stored in the neighboring base station storage means;
A reception buffer that, when determined to be true by the base station determination means, returns a confirmation message to request reception of the next data packet to the distribution server in order to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit. And a control means.

According to another embodiment of the mobile terminal of the present invention,
The peripheral base station storage means stores in advance the identifiers of a plurality of peripheral base stations,
The base station determination unit determines whether or not the identifiers of the plurality of neighboring base stations searched by the wireless communication unit and the identifiers of the plurality of neighboring base stations stored in the neighboring base station storage unit are the same. Is also preferable.

According to another embodiment of the mobile terminal of the present invention,
The peripheral base station storage means stores in advance an identifier of one connected base station and an identifier of a plurality of adjacent base stations,
The base station determination means includes an identifier of the connection base station and the identifiers of the plurality of adjacent base stations searched by the wireless communication unit, and an identifier of the connection base station and an identifier of the plurality of adjacent base stations stored in the peripheral base station storage means. It is also preferable to determine whether or not all match.

According to another embodiment of the mobile terminal of the present invention,
The reception buffer unit can set the allowable amount variably,
The reception buffer control means preferably increases the allowable amount of the reception buffer unit when it is determined to be true by the base station determination means.

According to another embodiment of the mobile terminal of the present invention,
The base station searched by the wireless communication unit is preferably a base station of a wide area network and / or an access point of a narrow area network.

According to another embodiment of the mobile terminal of the present invention,
Further comprising communication quality degradation recording means for recording whether or not communication quality degradation is detected by the wireless communication unit within a predetermined time after being determined to be true by the base station determination means;
It is also preferable that the peripheral base station storage means deletes the identifiers of the peripheral base stations whose communication quality deterioration has not been detected a predetermined number of times or more by the communication quality deterioration recording means.

According to another embodiment of the mobile terminal of the present invention,
The portable terminal further includes vehicle boarding recognition means for recognizing whether or not the user carrying the portable terminal has boarded the vehicle,
It is also preferable that the base station determination means determines the coincidence of the identifiers of the neighboring base stations only when the vehicle boarding recognition means recognizes that the boarding is in progress.

According to the present invention,
A wireless communication unit that searches for a nearby base station and connects to the base station via a wireless link;
In a program for causing a computer mounted on a portable terminal having a reception buffer unit to temporarily buffer a data packet received from a distribution server via a base station using a wireless communication unit,
Peripheral base station storage means for storing in advance an identifier of a searchable peripheral base station for the peripheral area of the communication quality degradation area;
Base station determination means for determining whether or not the identifier of the neighboring base station searched by the wireless communication unit matches the identifier of the neighboring base station stored in the neighboring base station storage means;
A reception buffer that, when determined to be true by the base station determination means, returns a confirmation message to request reception of the next data packet to the distribution server in order to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit. A computer is made to function as a control means.

According to the present invention,
A wireless communication unit connected to the base station via a wireless link;
In a reception buffer control method using a mobile terminal having a reception buffer unit for temporarily buffering a data packet received from a distribution server via a base station using a wireless communication unit,
The mobile terminal has a peripheral base station storage unit that stores in advance an identifier of a searchable peripheral base station for the peripheral area of the communication quality degradation area,
A first step in which a wireless communication unit searches for neighboring base stations;
A second step of determining whether or not the identifier of the searched neighboring base station matches the identifier of the neighboring base station stored in the neighboring base station storage means;
When it is determined to be true by the second step, a confirmation message to request reception of the next data packet is returned to the distribution server in order to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit. These steps are included.

  According to the mobile terminal, the program, and the method of the present invention, it is possible to control to accumulate data packets in the reception buffer as much as possible when entering the communication quality degradation area without recognizing the movement route of the mobile terminal. .

It is a spatial external view showing movement of a portable terminal. It is a spatial external view showing movement of a portable terminal in the present invention. It is a sequence diagram based on the movement of the portable terminal in FIG. It is a sequence diagram between a delivery server and a portable terminal. It is a functional block diagram of the portable terminal in this invention.

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

  FIG. 2 is a spatial external view showing movement of the portable terminal in the present invention.

  According to FIG. 2, as in FIG. 1, the mobile terminal 1 is present in, for example, a traveling car and receives radio waves from a plurality of base stations (or access points) 2 around the road. . The portable terminal 1 is not limited to a smartphone, and may be a tablet terminal or a personal computer, for example. The base station 2 may be a base station of a wide area network such as a mobile phone network or WiMAX, or may be an access point of a narrow area network such as a wireless LAN. Further, the mobile terminal 1 may be capable of performing handover between different networks by combining these base stations.

The distribution server 3 distributes data packets based on the application to the portable terminal 1 via the base station 2 via the Internet. The distribution server 3 may be, for example, the following server.
(1) Mail server that transmits and receives mail (2) Content server that distributes files and Web pages in file format (3) Streaming server that distributes video / audio in streaming format

According to the present invention, when the mobile terminal 1 that is receiving data packets from the distribution server 3 is located in the surrounding area before entering the communication quality degradation area, the data packet is stored in the reception buffer as much as possible. It is controlled to accumulate.
(1) The mobile terminal 1 transmits a new mail confirmation message to the mail server regardless of the normal received mail confirmation cycle, and promptly receives unreceived mail.
(2) The mobile terminal 1 returns a confirmation message for the data packet of the file being received to the content server at short time intervals, receives the remaining data packets, and stores them in the buffer.
(3) The mobile terminal 1 returns a confirmation message about the streaming data packet being received to the streaming server at short time intervals, receives the data packet as much as possible, and stores it in the buffer.
Note that when the data packet is accumulated in the reception buffer, the allowable amount of the reception buffer may be increased.

Here, in order to recognize that the mobile terminal 1 is located in the surrounding area of the communication quality deterioration area, the base station identifier of the surrounding base station is used according to the present invention. The mobile terminal 1 stores in advance peripheral base station information searched in the peripheral area of the communication quality deteriorated area. The peripheral base station information is a set of one or more base station identifiers, for example, a table as follows.
[Base Station 2A, Base Station 2B, Base Station 2C]
[Base station 2E, Base station 2G, Base station 2Q]
[..., ..., ...]
The peripheral base station information may be received in advance from a communication carrier, for example. This is because the telecommunications carrier already recognizes the surrounding area of the communication quality degradation area in the design of the base station arrangement. It is preferable that the peripheral base station information is appropriately updated by the communication carrier.

Further, by distinguishing between the connecting base station and the adjacent base station, it is possible to specify a more detailed surrounding area.
(Connection base station) (Adjacent base station 1) (Adjacent base station 2)
[Base Station 2A, Base Station 2B, Base Station 2C]
[Base station 2E, Base station 2G, Base station 2Q]
[..., ..., ...]
For example, even if the sets of base station identifiers match, if the base station identifiers of the connecting base stations are different, they are not determined to match.

Furthermore, in addition to the base station identifier, “regional range based on latitude and longitude” may be added to the peripheral base station information.
(Connected base station) (adjacent base station 1) (adjacent base station 2) (latitude longitude) (latitude longitude)
[Base Station 2A, Base Station 2B, Base Station 2C, XXX.YYY XXX.YYY]
[Base Station 2E, Base Station 2G, Base Station 2Q, XXX.YYY XXX.YYY]
[..., ..., ..., ...]
In this case, the mobile terminal 1 needs to further include a GPS (Global Positioning System) positioning unit. When the base station identifier of the searched neighboring base station matches the base station identifier registered in the neighboring base station information, the portable terminal 1 activates the GPS positioning unit and measures the latitude and longitude at that time. . Then, the mobile terminal 1 determines whether or not the measured latitude / longitude is included in the latitude / longitude position range registered in the peripheral base station information. In this case, it is possible to specify the area range that is finer than the base station identifier.

  FIG. 3 is a sequence diagram based on the movement of the mobile terminal in FIG.

According to FIG. 3, it is assumed that the mobile terminal 1 stores, for example, as follows, as peripheral base station information searched in the peripheral area of the communication quality degradation area.
[Base Station 2A, Base Station 2B, Base Station 2C]

<Location A> The mobile terminal 1 searches the base stations 2B, 2D, and 2E as neighboring base stations. Here, the mobile terminal 1 does not match the identifier (2B, 2D, 2E) of the searched neighboring base station with the identifier (2A, 2B, 2C) of the neighboring base station stored as the neighboring base station. Therefore, no special processing is executed.

<Position B> Thereafter, the mobile terminal 1 searches the base stations 2A, 2B, and 2C as neighboring base stations. Here, in the mobile terminal 1, the identifiers (2A, 2B, 2C) of the searched neighboring base stations match the identifiers (2A, 2B, 2C) of the neighboring base stations stored as the neighboring base stations. For this purpose, it is recognized that the data packet being received from the distribution server 3 is accumulated in the reception buffer as much as possible before it enters the communication quality degradation area and is recognized to be located in the surrounding area. According to FIG. 3, by sending back an acknowledgment (Ack) message at short time intervals, data packets are received as much as possible and stored in a buffer.

  FIG. 4 is a sequence diagram between the distribution server and the portable terminal. Here, a sequence like a radio broadcast of radiko (registered trademark) or Lisemo wave (registered trademark) is shown, for example.

  FIG. 4A shows a sequence between the distribution server 3 and the portable terminal 1 in the prior art. For example, when a reception buffer for 3 minutes is set by radiko, the portable terminal 1 transmits a confirmation message to the distribution server 3 at the timing when about 70 to 80% of the reception buffer for 3 minutes is reproduced, and for the next 3 minutes. Trying to get a data packet. In this case, after entering the communication quality degradation area, when the offline state continues for 1 to 2 minutes, the reception buffer becomes empty and streaming reproduction stops.

  On the other hand, FIG. 4B shows a sequence between the distribution server 3 and the portable terminal 1 in the present invention. When it is determined that the mobile terminal 1 is located in the peripheral area of the communication quality degradation area, the mobile terminal 1 returns a confirmation message at a short time interval in order to accumulate data packets up to the allowable amount of the reception buffer. In this case, even after the mobile terminal 1 enters the communication quality degradation area, the reception buffer is not immediately emptied, and the reproduction is continued as much as possible. Thereafter, when the mobile terminal 1 escapes from the communication quality degradation area, the process returns to the normal reception buffer control.

  In addition, what is arrange | positioned in the station yard in a subway is also effective as the access point as the base station 2. For example, it is assumed that an identifier of an access point arranged in a subway station is registered as peripheral base station information. It is assumed that the user who has the mobile terminal 1 is on the subway. Here, every time the subway stops at the station, the mobile terminal 1 is located in the peripheral area of the communication quality deterioration area, and therefore can accumulate data packets up to the allowable amount of the reception buffer. For example, if the time interval between subway stations is about 3 minutes, the mobile terminal 1 accumulates streaming data of about 3 minutes, so that a streaming service is continuously provided even in the subway.

  FIG. 5 is a functional configuration diagram of the mobile terminal according to the present invention.

  According to FIG. 5, the mobile terminal 1 includes a wireless communication unit 10, a reception buffer unit 11, an application 12, a neighboring base station storage unit 13, a base station determination unit 14, a reception buffer control unit 15, a communication It includes a quality deterioration recording unit 16, a vehicle boarding recognition unit 17, and a sensor 18. These functional components excluding the wireless communication unit 10 and the sensor 18 are realized by executing a program that causes a computer mounted on the portable terminal to function. Also, the processing order of these functional components can be understood as a reception buffer control method.

[Wireless communication unit 10]
The wireless communication unit 10 searches for neighboring base stations and detects one connected base station and one or more adjacent base stations. The identifiers of the neighboring base stations are output to the base station determination unit 14.
The wireless communication unit 10 is connected to the connected base station via a wireless link, and receives a data packet based on the application from the distribution server 3 via the connected base station. The received data packet is output to the reception buffer unit 11.
Further, the wireless communication unit 10 outputs information on presence / absence of communication quality degradation to the communication quality degradation recording unit 16.

[Reception buffer unit 11]
The reception buffer unit 11 receives data packets from the wireless communication unit 10 and temporarily buffers them. The reception buffer unit 11 outputs the input data packet to the application unit 12 in a FIFO (First-In First-Out) format.

In addition, it is preferable that the reception buffer unit 11 variably sets the allowable amount in accordance with an instruction from the reception buffer control unit 15. The reception buffer unit 11 may increase the allowable amount by using not only a memory as a primary cache but also a memory or a storage disk as a secondary cache. For example, according to a moving image file such as a music clip of Lismo wave (registered trademark) or YouTube (registered trademark), the allowable amount can be increased regardless of the normal setting of the allowable amount of the reception buffer.
The reception buffer unit 11 may be a reception buffer of a reception socket in a transport layer such as TCP (Transmission Control Protocol).

[Application unit 12]
The application unit 12 may be a Web browser or an FTP (File Transfer Protocol) client.

[Nearby base station storage unit 13]
The peripheral base station storage unit 13 stores in advance identifiers of searchable peripheral base stations for the peripheral area of the communication quality degradation area. Here, it is also preferable to store in advance a plurality of peripheral base station identifiers. Further, the peripheral base station storage unit 13 may be stored in advance divided into one connected base station identifier and a plurality of adjacent base station identifiers.

  In addition, it is preferable that the neighboring base station storage unit 13 deletes the identifiers of neighboring base stations whose communication quality degradation is not detected more than a predetermined number of times by the communication quality degradation recording unit 16. For example, according to FIG. 2, even if it is the portable terminal 1 which exists in the surrounding area of a communication quality degradation area, unless it is drive | working on the road, it will not enter into a tunnel. In that case, even if it is determined by the base station determination unit 14 that the mobile terminal 1 is located in the peripheral area of the communication quality deterioration area, communication quality deterioration does not occur thereafter. When such a process is repeated a predetermined number of times or more, the portable terminal 1 does not need to increase the allowable amount of the reception buffer unit at that position. In this case, the peripheral base station storage unit 13 deletes the set of the peripheral base stations.

[Base station determination unit 14]
The base station determination unit 14 determines whether or not the identifier of the neighboring base station searched by the wireless communication unit 10 matches the identifier of the neighboring base station stored in the neighboring base station storage unit 13. For example, if only one neighboring base station matches, it may be determined to be true. If it is determined to be true, the result is output to the reception buffer controller 15.
Here, the base station determination unit 14 determines whether or not the identifiers of the searched plurality of neighboring base stations match the identifiers of the plurality of neighboring base stations stored in the neighboring base station storage unit 13 as a whole. It may be a thing. As a result, the surrounding area of the communication quality degradation area can be specified relatively narrowly.
The base station determination unit 14 also includes an identifier of the connected base station searched by the wireless communication unit 10 and an identifier of a plurality of adjacent base stations, an identifier of the connected base station stored in the peripheral base station storage unit 13, and a plurality of It is also preferable to determine whether or not the identifiers of adjacent base stations match as a whole. By specifying the connection identifier, the surrounding area of the communication quality degradation area can be specified more narrowly.
It is also preferable that the base station determination unit 14 determines the coincidence of the identifiers of the neighboring base stations only when the vehicle boarding recognition unit 17 recognizes that the boarding is in progress. That is, when the mobile terminal 1 is not on a vehicle or the like, the mobile terminal 1 may not enter the communication quality degradation area.

[Reception Buffer Control Unit 15]
When it is determined to be true by the base station determination unit 14, the reception buffer control unit 15 returns a confirmation message to be requested to receive the next data packet to the distribution server 3 (see FIG. 3 described above). Thus, control is performed to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit 11.
The reception buffer control unit 15 may increase the allowable amount of the reception buffer unit 11 when it is determined to be true by the base station determination unit 14.
Note that the reception buffer control unit 15 can control the reception buffer unit 11 by controlling the return timing of the confirmation message when the reception buffer control unit 15 is configured as a part of the transport layer similarly to the reception buffer unit 11. .

[Communication quality degradation recording unit 16]
The communication quality deterioration recording unit 16 records whether or not the communication quality deterioration is detected by the wireless communication unit 10 within a predetermined time after the base station determination unit 14 determines that it is true. As described above, the neighboring base station storage unit 13 uses the communication quality degradation recording unit 16 to delete the identifiers of neighboring base stations for which communication quality degradation has not been detected a predetermined number of times or more. This is because such a portable terminal 1 does not need to increase the reception buffer capacity at the position.

[Vehicle boarding recognition unit 17]
The vehicle boarding recognition unit 17 recognizes whether or not the user carrying the mobile terminal 1 has boarded the vehicle. As described above, the base station determination unit 14 determines that the identifiers of the neighboring base stations match only when the vehicle boarding recognition unit 17 recognizes that the boarding is in progress. This is because there is a high possibility of entering a tunnel or underground when boarding a vehicle. Whether or not the vehicle is on board is recognized by an external signal using the sensor 18.

[Sensor 18]
The sensor 18 is, for example, a traffic IC card (for example, Suica (registered trademark)), recognizes that it has boarded the vehicle by passing through the station ticket gate, and notifies the vehicle boarding recognition unit 17 to that effect. Output. Moreover, it may recognize that it boarded the vehicle by connecting to the network in a motor vehicle by near field communication. Furthermore, it may be recognized that the vehicle has been boarded by detecting that the vehicle is moving at a predetermined speed by the GPS positioning function.

  As described above in detail, according to the mobile terminal, the program, and the method of the present invention, the data buffer is received as much as possible when entering the communication quality degradation area without recognizing the movement route of the mobile terminal. It can be controlled so as to be stored in.

  Various changes, modifications, and omissions of the above-described various embodiments of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Mobile terminal 10 Wireless communication part 11 Reception buffer part 12 Application part 13 Peripheral base station memory | storage part 14 Base station determination part 15 Reception buffer control part 16 Communication quality degradation recording part 17 Vehicle boarding recognition part 18 Sensor 2 Base station, access point 3 Distribution server

Claims (9)

A wireless communication unit that searches for a nearby base station and connects to the base station via a wireless link;
In a mobile terminal having a reception buffer unit that temporarily buffers data packets received from a distribution server via the base station using the wireless communication unit,
Peripheral base station storage means for storing in advance an identifier of a searchable peripheral base station for the peripheral area of the communication quality degradation area;
Base station determination means for determining whether or not the identifier of the neighboring base station searched by the wireless communication unit matches the identifier of the neighboring base station stored in the neighboring base station storage means;
When it is determined to be true by the base station determination means, a confirmation message to request reception of the next data packet is returned to the distribution server in order to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit. And a reception buffer control means. The peripheral base station storage means stores in advance identifiers of a plurality of peripheral base stations,
The base station determination unit determines whether or not the identifiers of the plurality of neighboring base stations searched by the wireless communication unit and the identifiers of the plurality of neighboring base stations stored in the neighboring base station storage unit are the same. The mobile terminal according to claim 1, wherein the mobile terminal is determined. The peripheral base station storage means stores in advance an identifier of one connected base station and an identifier of a plurality of adjacent base stations,
The base station determination means includes an identifier of a connected base station and an identifier of a plurality of adjacent base stations searched by the wireless communication unit, an identifier of the connected base station and a plurality of adjacent bases stored in the peripheral base station storage means The mobile terminal according to claim 1, wherein it is determined whether or not the station identifiers are the same as each other. The reception buffer unit can set the allowable amount variably,
4. The mobile phone according to claim 1, wherein the reception buffer control unit increases an allowable amount of the reception buffer unit when it is determined to be true by the base station determination unit. 5. Terminal.   The mobile terminal according to any one of claims 1 to 4, wherein the base station searched by the wireless communication unit is a base station of a wide area network and / or an access point of a narrow area network. . Further comprising communication quality degradation recording means for recording whether or not communication quality degradation is detected by the wireless communication unit within a predetermined time after being determined to be true by the base station determination means;
The said neighboring base station storage means deletes the identifier of the neighboring base station from which the communications quality degradation has not been detected a predetermined number of times or more by said communications quality degradation recording means. The portable terminal according to item. The portable terminal further includes vehicle boarding recognition means for recognizing whether or not a user carrying the portable terminal has boarded the vehicle,
7. The base station determination unit according to claim 1, wherein the base station determination unit determines that the identifiers of neighboring base stations coincide with each other only when the vehicle boarding recognition unit recognizes that the vehicle is on board. Mobile devices. A wireless communication unit that searches for a nearby base station and connects to the base station via a wireless link;
In a program for causing a computer mounted on a portable terminal having a reception buffer unit to temporarily buffer a data packet received from a distribution server via the base station using the wireless communication unit,
Peripheral base station storage means for storing in advance an identifier of a searchable peripheral base station for the peripheral area of the communication quality degradation area
Base station determination means for determining whether or not the identifier of the neighboring base station searched by the wireless communication unit matches the identifier of the neighboring base station stored in the neighboring base station storage means;
When it is determined to be true by the base station determination means, a confirmation message to request reception of the next data packet is returned to the distribution server in order to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit. A program for a portable terminal, which causes a computer to function as a receiving buffer control means. A wireless communication unit connected to the base station via a wireless link;
In the reception buffer control method using a portable terminal having a reception buffer unit for temporarily buffering a data packet received from the distribution server via the base station using the wireless communication unit,
The mobile terminal has a peripheral base station storage unit that stores in advance an identifier of a searchable peripheral base station for the peripheral area of the communication quality degradation area,
A first step in which the wireless communication unit searches for neighboring base stations;
A second step of determining whether or not the identifier of the searched neighboring base station matches the identifier of the neighboring base station stored in the neighboring base station storage means;
When it is determined to be true by the second step, a confirmation message to request reception of the next data packet is returned to the distribution server in order to buffer the data packet as much as possible up to the allowable amount of the reception buffer unit. A reception buffer control method for a portable terminal, comprising: a third step.

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