JP4653464B2 - Handover control method and communication system - Google Patents

Description

The present invention relates to a handover control method and a communication system , and in particular, handover control suitable for high-speed data communication performed between a mobile station and a base station mounted on a railway, an automobile, or the like moving at a high speed on a predetermined route The present invention relates to a method and a communication system .

  In recent years, the use of data communication in a mobile environment has increased, and a further high-speed data communication service has been demanded. The transmission speed of the third generation mobile communication system is several hundred kbps when moving at high speed, and at most 1-2 Mbps even when stationary.

  On the other hand, in a wireless LAN system, a transmission speed of several tens of Mbps can be realized, but it takes time for handover, and frequent handovers must be performed, and transmission efficiency decreases in a high-speed moving environment.

  FIG. 6 is a block diagram showing a configuration of a mobile station disclosed in Patent Document 1 below. In the mobile station terminal 601 shown in FIG. 6, the baseband signal processing unit 602 periodically measures the strength of the received signal from the base station, and the relative change amount calculation unit 603 receives the baseband processing unit 602. The relative change amount for each measurement time of the intensity of the received signal measured in this way is calculated. Then, the handover process is performed based on the received signal strength and the relative change amount of the received signal strength.

  As described above, the handover is performed by the mobile station measuring the electric field strength of a signal periodically transmitted from a plurality of base stations, and the communication quality with the currently connected base station is degraded. When it is determined that the communication quality is better when connected to the station, the handover is initiated by the mobile station, the handover destination base station information is notified to the mobile station management apparatus in the network, and the handover is performed.

  In the above scheme, the mobile station detects the handover destination base station, and transmits the handover destination base station information transmitted from the mobile station management device to the mobile station management device in the network. A handover destination of the mobile station is detected, and then a handover process is performed.

  FIG. 7 is a block diagram showing the configuration of the mobile communication system disclosed in Patent Document 2.

  The communication system shown in FIG. 7 is a system that focuses on how to secure radio resources of the next handover destination and improve the accuracy of handover at the time of handover.

For this reason, in the communication system shown in FIG. 7, it is predicted that the mobile station will move in any one of the plurality of wireless zones adjacent to the wireless zone where the mobile station 701 is located. Candidate zone notification means 703 for selecting a candidate radio zone that is a candidate for the destination of the mobile station, and notifying the candidate radio zone to the mobile station via the switching center 702, and a candidate for the destination candidate at the predicted time point Candidate zone selection means 704 is provided for selecting a radio zone, capturing a free radio channel, and forming a path in the communication link.
Japanese Patent No. 3127889 Japanese Patent Laid-Open No. 10-290475

  However, in the conventional method, since the handover process is performed after the handover is requested from the mobile station, the time until the handover is completed, that is, the time required for the handover becomes long, and the mobile station becomes high speed. When the mobile station moves frequently and frequently performs handover, there is a problem in that the throughput of data communication is lowered and the transmission efficiency is lowered.

The present invention has been made in view of this point, and an object of the present invention is to provide a handover control method and a communication system that can improve transmission efficiency by eliminating handover processing between a mobile station and a base station. To do.

According to the handover control method of the present invention, the first base station transmitting user data to a mobile station moving on a predetermined route has identification information for identifying the mobile station used for transmitting the user data ; , the position information of the mobile station, wherein the information identifying the first base station, need not start the process of switching the base station as a connection destination of the mobile station between the mobile station, the mobile a first step of notifying the station management device, before KiUtsuri Dokyoku management device, adjacent to the first base station, the connection is searching for a second base station that is expected, the search results, obtained was for the second base station, a second step of the first base station notifies the identification information used for transmission of the user data, the previous SL second base station, wherein Communication of the identification information used by the first base station for transmitting the user data. When subjected to, without doing the processing for switching the base station to the mobile station is itself the destination, from the second base station, to the destination the identification information indicates the user data addressed to the mobile station a third step of transmit and to comprise a.
A communication system according to the present invention is a communication system including a first base station, a second base station, and a base station management device, wherein the first base station moves along a predetermined route. When transmitting user data to a mobile station, identification information for identifying a mobile station used for transmitting the user data, position information of the mobile station, and information for identifying the first base station Even if the base station that is the connection destination of the mobile station is not started with the mobile station, the mobile station management device notifies the mobile station management device of the first base station. A second base station that is adjacent to the station and is predicted to be connected is searched. As a result of the search, the first base station uses the first base station to transmit the user data. And the second base station sends the first identification information When the ground station receives the notification of the identification information used for transmitting the user data, the mobile station can send the destination indicated by the identification information even if the mobile station has not performed a process of switching the base station to which the mobile station is connected. The user data addressed to the mobile station is transmitted.

  According to the present invention, the transmission efficiency can be improved by eliminating the handover process between the mobile station and the base station.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
1 to 3 are diagrams for explaining a handover control method according to Embodiment 1 of the present invention. FIG. 1 is a diagram showing an overall configuration of Embodiment 1. FIG. 2 is mobile station management. FIG. 3 is a block diagram showing a configuration of the apparatus 107, and FIG. 3 is a flowchart showing an operation flow of the first embodiment.

  1 and 2, reference numerals 101 to 103 denote base stations, 104 denotes a mobile station, 105 denotes a gateway device that connects to the network 106 and transmits user data to the base stations 101 to 103, and 107 denotes a mobile station management device. is there. Then, as shown in FIG. 2, the mobile station management apparatus 107 receives information for identifying the mobile station from the first base station 101 communicating with the mobile station 104 moving on a predetermined route, its position information, and Based on the information received by the information receiving unit 201 and the information receiving unit 201 that receives information for identifying its own station, the second base station 102 that is adjacent to the first base station 101 and is predicted to be connected is searched. An adjacent station search unit 202 to be determined and an adjacent station information notification unit 203 that notifies the mobile station information received to the second base station 102 obtained as a result of the search are configured.

  In FIG. 1, reference numerals 111, 112, and 113 denote service areas of the base stations 101, 102, and 1103, respectively.

  Next, the handover control method will be described using FIG. 1 and FIG.

  When the mobile station 104 is communicating with the base station 101, the base station 101 sequentially receives the information (MAC address: MAC # 0) of the mobile station 104 and the information (MAC # 1) of the local station, and the mobile station management device 107. (Step ST301). The mobile station management apparatus 107 that has received this information via the information receiving unit 201 has entered a predetermined area (overlap zone) in the service area 111 of the base station 101 (first base station) that is currently communicating. Is detected, the adjacent station search unit 202 searches the base station 102 (second base station), which is an adjacent base station, from the position information of the mobile station 104. Then, the adjacent station information notification unit 203 of the mobile station management apparatus 107 notifies the base station 102 of mobile station information (MAC # 0) (step ST302).

  On the other hand, the gateway device 105 transmits user data addressed to the mobile station 104 to the mobile station MAC address (MAC # 0). Therefore, the base station 101 transmits user data addressed to the mobile station 104 to the mobile station 104. On the other hand, the base station 102 discards the user data addressed to the mobile station 104 until notified of the mobile station 104 information (MAC # 0). After being notified of (MAC # 0), user data (MAC # 4 to MAC # 0) addressed to mobile station 104 is transmitted (step ST303). In addition, the base station 103 receives user data (MAC # 4 to MAC # 0) from the gateway device 105, but does not receive information (MAC # 0) of the mobile station 104 from the mobile station management device 107. The received user data (MAC # 4 to MAC # 0) is discarded.

  The location information of the mobile station is the location information acquired from the railroad control system in the case of a railway, the location information acquired from the GPS or in-vehicle navigation system in the case of an automobile, and the mobile phone in the train or automobile. In this case, position information acquired from GPS may be used. Moreover, you may comprise so that the information which shows a moving direction may be included.

  As described above, according to the first embodiment, it is not necessary to start processing for handover from the mobile station 104, and it is not necessary to perform processing for handover between the mobile station 104 and the base station 101. Therefore, the transmission efficiency can be improved.

  In the first embodiment, the MAC address has been described as an example of mobile station information. However, the present invention is not limited to this, and specific ID information for communication with the mobile station, information on encryption (encryption key), etc. It may be configured so as to include information necessary for communication with a mobile device, which is assigned to each station.

(Embodiment 2)
FIG. 4 is a diagram for explaining a handover control method according to Embodiment 2 of the present invention. Note that the same parts as those in FIG. The mobile station management apparatus 107 has the same configuration as that shown in FIG.

  In the first embodiment, the base station 101 and the base station 102 belong to the same segment, and the data addressed to the mobile station 104 (via the base station 101) from the gateway device 105 reaches the base station 102. ing. On the other hand, in the second embodiment, a layer 2 switch (or hub) 401 is provided between each base station and the gateway device 105 and is configured not to reach the base station 102. Different from 1.

  Hereinafter, the operation of the second embodiment will be described.

  When the mobile station 104 is communicating with the base station 101, the base station 101 sequentially notifies the mobile station management apparatus 107 of the information (MAC # 0) of the mobile station 104 and the information of the own station (MAC # 1). ing. When the mobile station management device 107 that has received this information via the information receiving unit 201 detects that the mobile station management device 107 has entered a predetermined area (overlap zone) of the service area 111 of the currently communicating base station 101, The search unit 202 searches for the base station 102 that is an adjacent base station from the position information of the mobile station 104. Then, the adjacent station information notification unit 203 of the mobile station management apparatus 107 notifies the base station 102 of the information (MAC # 0) of the mobile station 104, and at the same time, the mobile station 104 communicates with the layer 2 switch 401. Information on possible base stations 101 and 102 is notified. Upon receiving this information, the layer 2 switch 401 copies the user data (MAC # 4 to MAC # 0) and transmits the user data (MAC # 4 to MAC # 0) to both base stations 101 and 102. Send.

  The gateway device 105 transmits user data addressed to the mobile station to the mobile station 104, but the layer 2 switch 401 transmits user data addressed to the mobile station 104 to the base stations 101 and 102. Therefore, the base station 102 also transmits data addressed to the mobile station 104.

  As described above, according to the second embodiment, it is not necessary to start processing for handover from the mobile station 104, and it is not necessary to perform processing for handover between the mobile station 104 and the base station 101. Therefore, the transmission efficiency can be improved.

(Embodiment 3)
FIG. 5 is a diagram for explaining a handover control method according to Embodiment 3 of the present invention. Note that the same parts as those in FIG.

  In the second embodiment, a layer 2 switch is provided. However, the third embodiment is different from the second embodiment in that the base station is configured to operate as a layer 3 switch or a router. That is, the gateway device 105, the base station 101, the base station 102, and the base station 103 all have a function as an IP router or a layer 3 switch.

  The gateway device 105 recognizes that the mobile station 104 (IP # 0) is in the cell of the base station 101 and the base station 102 based on the mobile station information from the mobile station management device 107, and the base station 101 (MAC The data addressed to the mobile station 104 (IP # 0) is copied and transmitted to each of # 1) and the base station 102 (MAC # 2). Each base station receives only the user data addressed to itself, and transmits the received user data wirelessly if the IP address of the received user data is the mobile station information (IP # 0) notified from the mobile station management apparatus 107. Since other operations are the same as those of the second embodiment, description thereof is omitted.

  In Embodiment 1 and Embodiment 2, in the second step, the mobile station management device searches for a second base station that is adjacent to the first base station and is predicted to be connected, and as a result of the search, The obtained second base station is notified of the received mobile station information. However, as shown in FIG. 5, when moving from the service area of the base station under the gateway device 105 to the service area of a base station under another gateway device (not shown), the mobile station management device 107 By notifying the mobile station information to the gateway apparatus and base station that newly communicate, the handover can be reliably performed.

  Thus, according to the third embodiment, it is not necessary to start processing for handover from the mobile station 104, and it is not necessary to perform processing for handover between the mobile station 104 and the base station 101. Therefore, the transmission efficiency can be improved.

  The present invention is particularly suitable for use in high-speed mobile communication such as high-speed data communication and wireless LAN performed between a mobile station and a base station mounted on a railway, automobile, etc., moving at high speed on a predetermined route. It is.

The figure which shows the whole structure of the handover control method which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the mobile station management apparatus which concerns on Embodiment 1 of this invention. Flow chart showing the operation of the handover control method according to the first embodiment of the present invention. The figure which shows the whole structure of the handover control method which concerns on Embodiment 2 of this invention. The figure which shows the whole structure of the handover control method which concerns on Embodiment 3 of this invention. Block diagram showing prior art Block diagram showing prior art

Explanation of symbols

101, 102, 103 Base station 104 Mobile station 105 Gateway device 106 Network 107 Mobile station management device 111, 112, 113 Service area

Claims (3)

The first base station transmitting user data to a mobile station that moves a predetermined route, and identification information identifying the mobile station is used for transmission of the user data, and location information of the mobile station , said information identifying the first base station, you need not start the process of switching the base station as a connection destination of the mobile station between the mobile station, the first to notify the mobile station management unit And the process of
Before KiUtsuri Dokyoku management device, the first adjacent base station, the connection is searching for a second base station that is expected as a result of the search, for the obtained second base station, A second step of notifying the identification information used by the first base station for transmitting the user data ;
Before Stories second base station, if the first base station is notified of the identification information used for transmission of the user data, it switches the base station to the mobile station is itself the destination processing even without performing, from said second base station, to the destination the identification information indicates, a third step of sending the user data addressed to the mobile station,
A handover control method comprising: The second base station receives user data addressed to the mobile station regardless of whether or not it is communicating with the mobile station, and discards the received user data until the identification information is received. After receiving the identification information, the user data is transmitted to the destination indicated by the received identification information
The handover control method according to claim 1. A communication system comprising a first base station, a second base station, and a base station management device,
When the first base station is transmitting user data to a mobile station moving on a predetermined route, the first base station identifies identification information for identifying the mobile station used for transmitting the user data, and the mobile station Even if the process of switching the location information and the information for identifying the first base station to the mobile station to which the mobile station is connected is not started, the mobile station management apparatus Notify
The base station management device searches for a second base station that is adjacent to the first base station and is predicted to be connected to the second base station obtained as a result of the search. One base station notifies the identification information used for transmission of the user data;
The second base station, when receiving the notification of the identification information used by the first base station for transmitting the user data, the mobile station performs a process of switching a base station to which the mobile station is connected. Even if not, the user data addressed to the mobile station is transmitted to the destination indicated by the identification information.
Communications system.

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