JP2006041742A - Handover method, wireless base station, and wireless terminal station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a handover method capable of performing handover processing in a short time even under a high speed mobile environment. <P>SOLUTION: The handover method includes the steps of: a border wireless base station at a border part of a subnet for registering border information denoting that its own station is located at the border part of the subnet; the border wireless base station setting the border information to a transmission frame and transmitting the frame to a wireless terminal station; the wireless terminal station receiving the transmission frame and storing the border information when it is discriminated that its own station is located at the border part of the subnet; the wireless terminal station for storing the border information handing over a different subnet; the wireless terminal station making handover establishing connection to the wireless base station wherein its own station is contained; the wireless terminal station transmitting a position registration request to a host provided with a home agent function; and the host carrying out the position registration processing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a handover method, a radio base station, and a radio terminal station, and more particularly, a radio communication system in which radio base stations are distributed and accommodated in a plurality of subnets, and movement control of the radio terminal stations between the subnets is performed by mobile IP. And a radio base station and a radio terminal station for realizing the same.

  2. Description of the Related Art Conventionally, a wireless LAN system in which a plurality of wireless base stations distributed and accommodated in a plurality of subnets are arranged two-dimensionally and linearly and movement control between subnets is performed using mobile IP is used. In such a wireless LAN system, conventionally, the movement control in the wireless LAN, the L2SW switch learning process, and the movement control by the mobile IP operate independently.

  When the wireless terminal station becomes unable to communicate with the handover source wireless base station, the wireless terminal station searches for nearby wireless base stations, selects the most appropriate wireless base station as the handover destination wireless base station, and reconnects. . Here, if the handover source radio base station and the handover destination radio base station are in the same subnet, when the radio terminal station starts communication of main data via the handover destination radio base station, the L2SW The MAC address signal of the wireless terminal station is received from a port different from the above, and this is used as a trigger to switch learning.

  On the other hand, when the handover source radio base station and the handover destination radio base station are in different subnets, the radio terminal station connects to the handover destination radio base station and then transmits the main data via the handover destination radio base station. Although communication is started, the packet is not transferred to the foreign agent (FA) in the handover destination subnet because it is not registered. Therefore, the wireless terminal station receives an agent advertisement from the foreign agent (FA) that is the handover destination, and performs a registration operation to the foreign agent (FA) and the home agent (HA) that are the handover destination. When registration with the foreign agent (FA) and home agent (HA) is completed, the wireless terminal station can perform main data communication via the handover destination wireless base station (see, for example, Non-Patent Document 1). ).

IEEE 802.11 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications 1999 Edition

  By the way, in the conventional wireless LAN system as described above, for example, when the laptop computer used in the office is used in a quasi-stationary environment such as a hot spot service at a business trip destination, the above operation is particularly effective. There is no problem.

  On the other hand, when trying to apply a wireless LAN to a mobile environment, a wireless terminal station in communication switches the wireless base station to maintain communication with movement, and a handover process in a short time is required. However, in the conventional wireless LAN system, re-registration to the home agent (HA) is performed after receiving the agent advertisement from the foreign agent (FA). For this reason, when a wireless LAN is applied to a mobile environment, there are problems such as that it takes time for handover processing, the instantaneous interruption time during high-speed movement becomes long, and proper handover cannot be performed. Further, in the conventional wireless LAN system, L2SW learning is performed at the time of handover, but there is a problem that learning switching to the handover destination may not be performed in the case of unidirectional traffic.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a handover method capable of executing a handover process in a short time even in a high-speed moving environment, and a radio base station and a radio terminal station that implement the handover method. . Another object of the present invention is to obtain a handover method capable of learning switching to a handover destination even when the traffic is in one direction, and a radio base station and a radio terminal station that implement this method.

  In order to solve the above-described problems and achieve the object, a handover method according to the present invention includes a plurality of radio base stations that perform radio communication with radio terminal stations that can move between subnets by mobile IP control, and A handover method in a wireless communication system in which a plurality of subnets provided with router devices for transferring data packets transferred via a base station are interconnected via a core network, wherein the wireless terminal station exists in a visited subnet A boundary radio base station at the boundary of the subnet registers boundary information indicating that the local station is located at the boundary of the subnet with the own station, and the boundary radio base station Transmitting to a radio terminal station accommodated in the boundary radio base station by setting it as a transmission frame; and Storing the boundary information when it is determined that the local station is located at the boundary of the subnet based on the presence or absence of boundary information, and the step of handing over the wireless terminal station storing the boundary information to a different subnet A wireless terminal station handed over to a different subnet establishes a connection with the wireless base station accommodated in the handover destination subnet, and a wireless terminal station that establishes a connection with the handover destination wireless base station Transmitting a location registration request of the local station to a host having a home agent function existing in the home network of the wireless terminal station, and a step of performing location registration processing by the host that has received the location registration request. It is characterized by.

  According to the present invention, the wireless terminal station located at the boundary of the subnet determines whether or not the local station is at the boundary of the subnet based on the boundary information included in the beacon. The wireless terminal station that has determined that the local station is at the boundary of the subnet transmits a location registration message for registering the location of the local station when handed over to a different subnet.

  According to the present invention, even when a handover across subnets occurs, the wireless terminal station can perform location registration without waiting for an agent advertisement from a foreign agent. Thereby, the processing time for performing location registration can be greatly shortened, and the instantaneous interruption time of data communication at the time of handover across subnets can be significantly shortened. Therefore, according to the present invention, even when a wireless LAN is applied to a high-speed moving environment, handover processing can be executed in a short time, and the instantaneous interruption time of user data at the time of handover across subnets can be reduced. There is an effect that speeding up of the handover can be achieved.

  Hereinafter, embodiments of a handover method, a radio base station, and a radio terminal station according to the present invention will be described in detail based on the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a system configuration of a wireless LAN system that is a wireless communication system according to a first embodiment of the present invention.

As shown in FIG. 1, the wireless communication system according to this embodiment includes a core network 100, which is an IP network, a terminal station 110a, a home agent 160 (HA 160), and a foreign agent (a) 150a (FA). (A) 150a), foreign agent (b) 150b (FA (b) 150b), L2SW (a) 140a, L2SW (b) 140b, and radio base station (a) 120a (AP (a) 120a )When,
Radio base station (b) 120b (AP (b) 120b), radio base station (c) 120c (AP (c) 120c), radio base station (d) 120d (AP (d) 120d), radio base station A station (e) 120e (AP (e) 120e) and a wireless terminal station 130 (STA 130) are constructed. A plurality of radio base stations (AP) 120 are arranged in a plane and a line so that the radio terminal station (STA) 130 can be handed over. In the following, the radio base station (a) 120a, the radio base station (b) 120b, the radio base station (c) 120c, the radio base station (d) 120d, and the radio base station (e) 120e May be collectively referred to as a radio base station (AP) 120.

  Here, the core network 100 is an IP network, and is a network that interconnects network connection devices. The terminal station 110a is a terminal on the IP network. The foreign agent (a) 150a is a foreign agent in the subnet that the wireless terminal station 130 visited before the handover, and is a host having a foreign agent function of mobile IP. The foreign agent (b) 150b is a foreign agent in a subnet visited by the wireless terminal station 130 after the handover, and is a host having a foreign agent function of mobile IP.

  The L2SW (a) 140a and the L2SW (b) 140b are layer 2 switches that accommodate a plurality of radio base stations (AP) 120. The wireless base station (a) 120a, the wireless base station (b) 120b, the wireless base station (c) 120c, the wireless base station (d) 120d, and the wireless base station (e) 120e are wireless LAN base stations. It is a point. The wireless terminal station 130 (STA 130) is a wireless LAN mobile terminal.

  FIG. 2 shows a configuration diagram showing internal functions of the radio base station (AP) 120. As shown in FIG. 2, the radio base station 120 is connected to a wireless LAN PHY unit 300, a network IF 310, a MAC frame reception unit 320, a MAC frame generation unit 330, a boundary registration unit 340, and a beacon transmission unit 350. And a control unit 360.

  Here, the wireless LAN PHY unit 300 is a physical layer processing unit of the wireless LAN. The network IF 310 is an interface processing unit with the core network 100. The MAC frame receiving unit 320 is a processing unit that performs reception MAC processing and separates a main signal and a control signal. The MAC frame generation unit 330 is a processing unit that receives a control signal and a main signal and performs transmission MAC processing.

  The boundary registration unit 340 is a storage unit that registers boundary information indicating that the own wireless base station (AP) 120 is a boundary wireless base station located at the boundary of the subnet. The beacon sending unit 350 is a processing unit that generates beacon contents from the radio base station information of the own radio base station (AP) 120 and the boundary information obtained from the boundary registration unit 340. The connection control unit 360 is a processing unit that transmits and receives control information related to the connection with the wireless terminal station (STA) 130 and performs connection processing and handover processing of the wireless terminal station (STA) 130.

  FIG. 3 is a configuration diagram showing internal functions of the wireless terminal station (STA) 130. As shown in FIG. 3, the wireless terminal station (STA) 130 includes a wireless LAN PHY unit 400, a network IF 410, a MAC frame generation unit 420, a MAC frame reception unit 430, a beacon processing unit 440, and a registration frame generation unit. 450 and a connection control unit 460.

  Here, the wireless LAN PHY unit 400 is a physical layer processing unit of the wireless LAN. The network IF 410 is an interface processing unit with a terminal connected to the wireless terminal station (STA) 130. The MAC frame generation unit 420 is a processing unit that receives a control signal and a main signal and performs transmission MAC processing. The MAC frame receiving unit 430 is a processing unit that performs reception MAC processing and separates the main signal and the control signal.

  The beacon processing unit 440 determines whether or not the own wireless terminal station (STA) 130 is located at the boundary of the subnet from the received beacon. Further, the processing unit notifies the connection control unit 460 of the determination result and the content of the received beacon. The connection control unit 460 is a processing unit that performs transmission / reception of control information related to connection with the radio base station (AP) 120 and performs connection processing and handover processing with the radio base station (AP) 120. Also, the connection control unit 460 notifies the registration frame generation unit 450 of the completion of connection with the radio base station (AP) 120. The registration frame generation unit 450 receives a notification of completion of connection with the radio base station (AP) 120 from the connection control unit 460 and generates a location registration frame for registering the location of the local station. This is a functional unit that transmits to the agent 160 or the foreign agent 150.

  Next, the operation of the wireless LAN system according to this embodiment constructed as described above will be described. First, characteristic processing at the time of constructing a wireless LAN system will be described with reference to FIG. FIG. 4 is a flowchart for explaining a characteristic process at the time of constructing the wireless LAN system according to the present embodiment. First, a wireless LAN is constructed by arranging a plurality of wireless base stations (AP) 120 two-dimensionally and linearly so that handover of the wireless terminal station (STA) 130 is possible (step S101). At this time, the subnet configuration in which the radio base station (AP) 120 is accommodated is known in advance. Next, in the radio base station (AP) 120 serving as the subnet boundary, the boundary registration unit 340 informs the boundary information that the own radio base station (AP) 120 is a boundary radio base station located at the subnet boundary. Is registered (step S102). In the system configuration shown in FIG. 1, for example, the radio base station (b) 120b and the radio base station (c) 120c are boundary radio base stations located at the boundary of the subnet. Therefore, the boundary information is registered in the boundary registration unit 340 of the radio base station (b) 120b and the radio base station (c) 120c.

  Here, the method for registering the boundary information is not particularly limited. For example, the boundary information is manually set when the radio base station (AP) 120 is installed. The method of setting etc. is mentioned. In addition, various methods can be used as long as boundary information can be registered accurately and reliably.

  Next, the operation after the start of wireless communication will be described with reference to FIG. FIG. 5 is a flowchart for explaining the operation of the wireless LAN system according to the present embodiment. The wireless terminal station (STA) 130 starts wireless communication within the communication area of the wireless base station (b) 120b, for example. In the radio base station (b) 120b and the radio base station (c) 120c in which the boundary information indicating the boundary of the subnet is registered in the boundary registration unit 340, the normal beacon is positioned at the boundary of the subnet. The beacon to which the boundary information shown is added is generated in the beacon sending unit 350 (step S111). Then, the generated beacon is notified as a wireless signal to the wireless terminal station 130 via the MAC frame generating unit 330 and the wireless LAN PHY unit 300 (step S112).

  That is, the beacon sending unit 350 generates a beacon in which boundary information indicating that the wireless base station (b) 120b and the wireless base station (c) 120c are located at the boundary of the subnet is added to a normal beacon, The beacon is transmitted (notified) as a radio signal to the radio terminal station 130 as a radio signal via the MAC frame generation unit 330 and the wireless LAN PHY unit 300.

  When the wireless terminal station (STA) 130 receives the beacon transmitted from the wireless base station (AP) 120 (step S113), the beacon is transmitted to the beacon process via the wireless LAN PHY unit 400 and the MAC frame receiving unit 430. Part 440. Then, the beacon processing unit 440 determines whether or not the own wireless terminal station (STA) 130 is located at the boundary of the subnet from the received beacon (step S114). That is, beacon processing section 440 determines whether or not boundary information is included in the beacon, and determines whether or not own wireless terminal station (STA) 130 is located at the boundary of the subnet. The beacon processing unit 440 determines that the own wireless terminal station (STA) 130 is located at the boundary of the subnet when the beacon includes boundary information. The beacon processing unit 440 determines that the own wireless terminal station (STA) 130 is not located at the boundary of the subnet when the beacon does not include boundary information.

  If it is determined that the own wireless terminal station (STA) 130 is located at the boundary of the subnet (Yes at step S114), the beacon processing unit 440 determines that a handover across the subnet boundary is performed. The boundary condition is notified to the connection control unit 460 (step S115). The connection control unit 460 stores this. Next, the wireless terminal station (STA) 130 performs handover to the wireless base station (AP) 120 in the adjacent subnet, that is, hands over the boundary of the subnet (step S116). Then, the wireless terminal station (STA) 130 establishes a connection with the handover destination wireless base station (AP) 120 in the connection control unit 460 (step S117).

  Next, when the connection between the wireless terminal station (STA) 130 and the wireless base station (AP) 120 is completed, the connection control unit 360 notifies the registration frame generation unit 450 of the completion of connection establishment (step S118). ). The registration frame generation unit 410 notified of the completion of connection establishment generates a location registration frame for location registration of the own wireless terminal station (STA) 130 and sends it to the MAC frame generation unit 330. The MAC frame generation unit 330 receives the location registration frame and generates a MAC frame of the location registration message. The location registration message is sent to the home agent 160 via the wireless LAN PHY unit 400 (step S119). The home agent 160 receives the location registration message and performs registration processing (step S120). Thereby, the wireless terminal station (STA) 130 can perform wireless communication in the handover destination subnet.

  On the other hand, when it is determined that the own wireless terminal station (STA) 130 is not located at the boundary of the subnet (No at step S114), the beacon processing unit 440 determines that the handover across the subnet boundary is not performed. Then, a normal handover operation that is conventionally performed is performed (step S121). Therefore, in this case, the location registration process to the home agent 160 is not performed.

  As described above, in the wireless communication system according to the present embodiment, the wireless terminal station (STA) 130 located at the boundary portion of the subnet determines that the local station is the subnet by the boundary information included in the beacon. It is judged whether it is in the boundary part of. If it is determined that the local station is at the boundary of the subnet and the handover is made to a different subnet, a location registration message for registering the location of the local station is transmitted. As a result, in the wireless communication system according to the present embodiment, even when a handover across subnets occurs, the wireless terminal station (STA) 130 does not wait for the agent advertisement from the foreign agent 150 and registers the location in the home agent 160. It can be performed. Therefore, the processing time for performing location registration can be greatly shortened, and the instantaneous interruption time of data communication at the time of handover across subnets can be greatly shortened. As a result, the radio communication system according to the present embodiment can execute handover processing in a short time even when applied to a high-speed mobile environment, and can reduce the instantaneous interruption time of user data at the time of handover across subnets. Yes, it is possible to speed up handover.

  Further, the wireless terminal station (STA) 130 may have a bridge function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, location registration is requested to the home agent 160 for each IP address of each terminal. As a result, the location can be registered in the home agent 160 without waiting for the agent advertisement from the foreign agent 150 as in the above case.

  The wireless terminal station (STA) 130 may have a router function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, location registration is requested with an address represented by the router. As a result, the location can be registered in the home agent 160 without waiting for the agent advertisement from the foreign agent 150 as in the above case.

  Furthermore, in the above description, the case where the boundary information is added to the beacon and transmitted is described, but it is also possible to adopt a form in which the information that is the boundary part of the subnet is added to the probe response frame and transmitted instead of the beacon. . Even in this case, since the wireless terminal station (STA) 130 can acquire boundary information, the same effect as described above can be obtained.

  In the present embodiment, a registration request message to the home agent 160 can be used as an L2SW learning frame.

Embodiment 2. FIG.
In the second embodiment, a modification of the first embodiment described above will be described. In the first embodiment described above, a case is described in which boundary information indicating that the own radio base station (AP) 120 is located at the boundary of the subnet is added to beacon information broadcast from the radio base station (AP) 120. did. In the present embodiment, in addition to the boundary information, the address information of the handover destination radio base station (AP) 120 for specifying the subnet radio base station (AP) 120 to be the handover destination is used as the handover source radio. The case where it adds to the beacon information alert | reported from the base station (AP) 120 is demonstrated.

  The basic configuration of the radio communication system, the configuration and function of the radio base station, and the configuration and function of the radio terminal station in the present embodiment are the same as those in the first embodiment. Therefore, as for these, reference is made to the description in FIGS. 1 to 3 and the first embodiment, and the detailed description is omitted here.

  In this wireless LAN system, address information for the wireless terminal station (STA) 130 to specify the wireless base station (AP) 120 located at the boundary of the subnet that is the handover destination of the wireless terminal station (STA) 130. Can be obtained before handover. That is, the wireless terminal station (STA) 130 obtains the address information of the wireless base station (AP) 120 located at the boundary of the subnet adjacent to the subnet to which the currently located wireless base station (AP) 120 belongs before the handover. Can be obtained.

  For example, in FIG. 1, when the wireless terminal station (STA) 130 is under the control of the wireless base station (b) 120b, the wireless base station (b) 120b adds the beacon to the boundary information of the own wireless base station (b) 120b. Thus, the address information (MAC address) of the radio base station (c) 120c located at the boundary of the subnet that is the handover destination is added and transmitted to the radio terminal station 130.

  The wireless terminal station (STA) 130 receives the beacon transmitted from the wireless base station (b) 120b and receives address information (MAC address) of the wireless base station (c) 120c located at the boundary of the subnet that is the handover destination. Can be known by the beacon before handover.

  The operation of the wireless LAN system that is the wireless communication system according to the present embodiment will be described below with reference to FIG. FIG. 6 is a flowchart for explaining the operation of the wireless LAN system according to the present embodiment. Here, a case where the wireless terminal station (STA) 130 moves from the communication area of the wireless base station (b) 120b to the communication area of the wireless base station (c) 120c will be described. First, the wireless terminal station (STA) 130 starts wireless communication within the communication area of the wireless base station (b) 120b. In the radio base station (b) 120b and the radio base station (c) 120c in which the boundary information is registered in the boundary registration unit 340 of the local station, boundary information indicating that the boundary information is located at the boundary of the subnet in the normal beacon, and handover The beacon sending unit 350 generates a beacon to which the address information (MAC address) of the wireless base station (c) 120c located at the boundary portion of the previous subnet is added (step S131). Then, the generated beacon is notified as a wireless signal to the wireless terminal station 130 via the MAC frame generating unit 330 and the wireless LAN PHY unit 300 (step S132).

  When the wireless terminal station (STA) 130 receives a beacon transmitted from the wireless base station (AP) 120 (step S133), the beacon is transmitted to the beacon process via the wireless LAN PHY unit 400 and the MAC frame receiving unit 430. Part 440. Then, the beacon processing unit 440 determines whether or not the own wireless terminal station (STA) 130 is located at the boundary of the subnet from the received beacon (step S134). That is, beacon processing section 440 determines whether or not boundary information is included in the beacon, and determines whether or not own wireless terminal station (STA) 130 is located at the boundary of the subnet. The beacon processing unit 440 determines that the own wireless terminal station (STA) 130 is located at the boundary of the subnet when the beacon includes boundary information. Also, the beacon processing unit 440 determines that the own wireless terminal station (STA) 130 is not located at the boundary portion of the subnet when the boundary information is not included in the beacon.

  Here, if it is determined that the own wireless terminal station (STA) 130 is located at the boundary of the subnet (Yes at step S134), the beacon processing unit 440 determines that the handover across the subnet boundary is performed. Then, it notifies the connection control unit 460 of the address information (MAC address) of the radio base station (c) 120c located at the boundary of the subnet that is the handover destination (step S135). The connection control unit 460 stores these pieces of information.

  Next, the wireless terminal station (STA) 130 hands over to the wireless base station (c) 120c in the adjacent subnet across the subnet boundary (step S136). Then, the connection control unit 460 establishes a connection with the handover destination radio base station (c) 120c (step 137). After the handover, the wireless terminal station (STA) 130 receives a beacon from the handover target wireless base station (c) 120c, and acquires address information (MAC address) of the wireless base station (c) 120c (step S138). Here, in the present embodiment, confirmation processing is performed to confirm that a handover across subnets has been performed. That is, the beacon processing unit 440 determines whether or not the address information (MAC address) matches the address information (MAC address) stored in the connection control unit 460 (step S139).

  Here, when the address information (MAC address) of the radio base station (c) 120c acquired by the beacon after the handover matches the address information (MAC address) stored in the connection control unit 460 (Yes in step S139). ), It is determined that a handover across the subnet has been performed.

  When the connection between the wireless terminal station (STA) 130 and the wireless base station (c) 120c is completed, the connection control unit 360 notifies the registration frame generation unit 450 of the completion of connection establishment (step S140). . The registration frame generation unit 410 notified of the completion of connection establishment generates a location registration frame for location registration of the own wireless terminal station (STA) 130 and sends it to the MAC frame generation unit 330. The MAC frame generation unit 330 receives the location registration frame and generates a MAC frame of the location registration message. The location registration message is sent to the home agent 160 via the wireless LAN PHY unit 400 (step S141). The home agent 160 receives the location registration message and performs registration processing (step S142). As a result, the wireless terminal station (STA) 130 can perform wireless communication in the handover destination subnet.

  On the other hand, when the address information (MAC address) of the radio base station (c) 120c acquired by the beacon after the handover does not match the address information (MAC address) stored in the connection control unit 460 (No in step S139). Then, it is determined that the handover beyond the subnet has not been performed, and the normal handover operation that has been performed conventionally is performed (step S143). Therefore, in this case, the location registration process to the home agent 160 is not performed.

  If it is determined that the own wireless terminal station (STA) 130 is not located at the boundary of the subnet (No at step S134), the beacon processing unit 440 determines that the handover across the subnet boundary is not performed. Then, a normal handover operation that is conventionally performed is performed (step S143). Therefore, in this case, the location registration process to the home agent 160 is not performed.

  As described above, in the wireless communication system according to the present embodiment, the beacon transmitted by the wireless base station (AP) 120 located before the wireless terminal station (STA) 130 is handed over is used as the handover destination. The address information (MAC address) of the radio base station (AP) 120 is notified. Thereby, the radio terminal station (STA) 130 can acquire the address information of the radio base station (AP) 120 accommodated in the handover destination and store it in the connection control unit 460 before performing the handover.

  The wireless terminal station (STA) 130 uses the address information (MAC address) of the wireless base station (AP) 120 acquired by the beacon after the handover and the address information (MAC address) stored in the connection control unit 460. By the confirmation processing that has been performed, it is possible to accurately confirm that a handover across subnets has occurred.

  When the wireless terminal station (STA) 130 can confirm that the handover across the subnet has occurred, the wireless terminal station (STA) 130 does not wait for the agent advertisement from the foreign agent 150 and does not wait for the home agent. At 160, location registration can be performed. Therefore, the processing time for performing location registration can be greatly shortened, and the instantaneous interruption time of data communication at the time of handover across subnets can be greatly shortened. As a result, the radio communication system according to the present embodiment can execute handover processing in a short time even when applied to a high-speed mobile environment, and can reduce the instantaneous interruption time of user data at the time of handover across subnets. Yes, it is possible to speed up handover.

  In the above description, the case where there is one radio base station (AP) that is a candidate for a handover destination across subnets has been described, but even when there are a plurality of radio base stations (AP) that are candidates for a handover destination. By enumerating each address information and adding it to the beacon, the same effect as described above can be obtained.

  Further, the wireless terminal station (STA) 130 may have a bridge function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, location registration is requested to the home agent 160 for each IP address of each terminal. As a result, the location can be registered in the home agent 160 without waiting for the agent advertisement from the foreign agent 150 as in the above case.

  The wireless terminal station (STA) 130 may have a router function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, location registration is requested with an address represented by the router. As a result, the location can be registered in the home agent 160 without waiting for the agent advertisement from the foreign agent 150 as in the above case.

  In the above description, the boundary information and the address information of the wireless base station (AP) 120 located at the boundary of the subnet that is the handover destination are added to the beacon and transmitted, but the probe response frame is used instead of the beacon. It is also possible to add the above information and transmit it. Even in this case, the wireless terminal station (STA) 130 can obtain the above-described information, so that the above-described effects can be obtained.

  In the present embodiment, a registration request message to the home agent 160 can be used as an L2SW learning frame.

Embodiment 3 FIG.
In the third embodiment, a case will be described in which a wireless base station (AP) receives an agent advertisement from a wired network and periodically notifies the wireless terminal station (STA) of this.

  The basic configuration of the radio communication system and the configuration and function of the radio terminal station in the present embodiment are the same as those in the first embodiment. Therefore, as for these, referring to the description in FIGS. 1 and 2 and the first embodiment, detailed description is omitted here. In addition, since a part of structure is different from the case of Embodiment 1, about a wireless base station, a different part is demonstrated.

  FIG. 7 is a configuration diagram showing internal functions of the radio base station (AP) 121 according to the present embodiment. As shown in FIG. 7, the wireless base station (AP) 121 includes a wireless LAN PHY unit 300, a network IF 310, a MAC frame reception unit 320, a MAC frame generation unit 330, a beacon transmission unit 350, and a connection control unit 360. And a router advertisement receiving unit 370. In FIG. 7, the same reference numerals as those in FIG. 1 are assigned to the same configurations as those in the first embodiment. In FIG. 1, the wireless base station (a) 120a to the wireless base station (e) 120e are replaced with the wireless base station (a) 121a to the wireless base station (e) 121e, respectively.

  The wireless base station (AP) 121 shown in FIG. 7 is different from the wireless base station (AP) 120 shown in FIG. 2 in that a router advertisement receiving unit 370 is provided instead of the boundary registration unit 340. Here, the router advertisement receiving unit 370 is a functional unit that receives an agent advertisement from the wired network.

  The operation of the wireless LAN system that is the wireless communication system according to the present embodiment will be described below with reference to FIG. FIG. 8 is a flowchart for explaining the operation of the wireless LAN system according to the present embodiment. The wireless terminal station (STA) 130 starts wireless communication within the communication area of the wireless base station (b) 121b, for example. On the wired network, the foreign agent (a) 150a and the foreign agent (b) 150b notify the agent advertisement in the subnet at a constant cycle (step S151). The radio base station (b) 121b receives the agent advertisement notified by the foreign agent (a) 150a at the router advertisement receiving unit 370 via the network IF 310. Similarly, the radio base station (c) 121c receives the agent advertisement notified by the foreign agent (b) 150b at the router advertisement receiving unit 370 via the network IF 310 (step S152).

  Then, the router advertisement receiving unit 370 of the radio base station (b) 121b notifies the beacon transmitting unit 350 of the local station of the received agent advertisement content of the foreign agent (a) 150a. Further, the router advertisement receiving unit 370 of the radio base station (c) 121c notifies the beacon sending unit 350 of the local station of the received agent advertisement content of the foreign agent 150 (b) 150b. Each beacon sending unit 350 generates a beacon in which the content of the agent advertisement is added to the beacon content of the local station. Then, the generated beacon is notified as a wireless signal to the wireless terminal station 130 via the MAC frame generating unit 330 and the wireless LAN PHY unit 300 (step S153). For example, when the agent advertisement period of the foreign agent (a) 150a is 1 second, the radio base station (b) 121b that has received it adds the agent advertisement content to its own beacon, for example, at a beacon period of 50 ms. The information can be notified to the wireless terminal station (STA) 130.

  When the wireless terminal station (STA) 130 performs wireless communication within the communication area of the wireless base station (b) 121b, the wireless terminal station (STA) 130 transmits a beacon transmitted from the wireless base station (b) 121b. Received (step S154), the information of the foreign agent (a) 150a of the subnet to which the radio base station (b) 121b belongs is detected from the contents of the beacon and stored (step S155). That is, when the wireless terminal station (STA) 130 receives the beacon transmitted from the wireless base station (b) 121b, the beacon is transmitted to the beacon processing unit 440 via the wireless LAN PHY unit 400 and the MAC frame receiving unit 430. Sent. The beacon processing unit 440 detects information on the foreign agent (a) 150a in the subnet to which the radio base station (b) 121b belongs from the received beacon. The beacon processing unit 440 notifies the connection control unit 460 of the information on the foreign agent (a) 150a. The connection control unit 460 stores this information.

  In such a state, the wireless terminal station 130 performs handover to the wireless base station (AP) 121 of the adjacent subnet across the boundary of the subnet (step S156), and the connection control unit 460 performs the wireless base station (AP) of the handover destination. Connection establishment with 121 is performed (step S157). Here, in the wireless terminal station (STA) 130, when reconnecting to the handover destination wireless base station (AP) 121 (or after reconnection), a beacon transmitted from the handover destination wireless base station (AP) 121. The router advertisement receiving unit 370 detects the information of the foreign agent 150 in the subnet to which the handover destination radio base station (AP) 121 belongs from the beacon content (step S158). Then, the router advertisement receiving unit 370 determines whether or not the information of the foreign agent 150 matches the information of the foreign agent 150 stored in the connection control unit 460 (step S159).

  In FIG. 1, a wireless terminal station (STA) 130 hands over to a wireless base station (c) 121c in an adjacent subnet and establishes a connection. The wireless terminal station (STA) 130 receives a beacon transmitted from the wireless base station (c) 121c when reconnecting (or after reconnecting) to the handover target wireless base station (c) 121c, Information on the foreign agent (b) 150b in the subnet to which the wireless base station (c) 121c belongs is detected from the contents of the beacon. Then, it is determined whether or not the information matches the information of the foreign agent 150 stored in the connection control unit 460 (step S160).

  Here, when the information of the foreign agent 150 of the handover destination does not match the information of the foreign agent 150 stored in the connection control unit 460 (No at Step S160), that is, in the beacon processing unit 440, When the information of the foreign agent 150 different from the information of the foreign agent a 150 (a) used so far is detected, the wireless terminal station (STA) 130 sends the wireless terminal to the home agent 160 by the registration frame generation unit 450. A location registration message for performing location registration of the station (STA) 130 is transmitted (step S161). The home agent 160 receives the location registration message and performs registration processing (step S162). Thereby, the wireless terminal station (STA) 130 can perform wireless communication in the handover destination subnet.

  On the other hand, when the information of the foreign agent 150 of the handover destination and the information of the foreign agent 150 stored in the connection control unit 460 match (Yes at Step S160), the wireless terminal station (STA) 130 It is determined that a handover beyond the subnet has not been performed, and a conventional normal handover operation is performed (step S163). Therefore, in this case, the location registration process to the home agent 160 is not performed.

  As described above, in the wireless communication system according to the present embodiment, the information of the foreign agent 150 is added to the beacon transmitted from the wireless base station (AP) 121 to the wireless terminal station (STA) 130. Send. The wireless terminal station (STA) 130 detects that a handover across subnets has occurred based on the information of the foreign agent 150 and sends a location registration message for performing location registration to the home agent 160. Accordingly, even when a handover across subnets occurs, the wireless terminal station (STA) 130 can perform location registration in the home agent 160 without waiting for an agent advertisement from the foreign agent 150. Therefore, the processing time for performing location registration can be greatly shortened, and the instantaneous interruption time of data communication at the time of handover across subnets can be greatly shortened. As a result, the radio communication system according to the present embodiment can execute handover processing in a short time even when applied to a high-speed mobile environment, and can reduce the instantaneous interruption time of user data at the time of handover across subnets. Yes, it is possible to speed up handover.

  Further, the wireless terminal station (STA) 130 may have a bridge function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, location registration is requested to the home agent 160 for each IP address of each terminal. As a result, the location can be registered in the home agent 160 without waiting for the agent advertisement from the foreign agent 150 as in the above case.

  The wireless terminal station (STA) 130 may have a router function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, location registration is requested with an address represented by the router. As a result, the location can be registered in the home agent 160 without waiting for the agent advertisement from the foreign agent 150 as in the above case.

  In the above, the case where the information of the foreign agent 150 is added to the beacon and transmitted has been described, but the above information may be added to the probe response frame and transmitted instead of the beacon. . Even in this case, the wireless terminal station (STA) 130 can obtain the above-described information, so that the above-described effects can be obtained.

  In the present embodiment, a registration request message to the home agent 160 can be used as an L2SW learning frame.

Embodiment 4 FIG.
In the fourth embodiment, a technique for speeding up handover in the same subnet will be described.

  The basic configuration of the radio communication system in the present embodiment is the same as that in the first embodiment. Therefore, as for this, referring to the description in FIG. 1 and Embodiment 1, the detailed description is omitted here. As the wireless terminal station (STA), a wireless terminal station having a conventional configuration that does not include the beacon processing unit 440 in the configuration illustrated in FIG. 3 is used. And about a radio base station, since it is set as the structure different from the structure shown in FIG. 2 of Embodiment 1, a different part is demonstrated.

  FIG. 9 shows a configuration diagram showing the internal functions of radio base station (AP) 122 in the present embodiment. As shown in FIG. 9, the wireless base station (AP) 122 includes a wireless LAN PHY unit 300, a network IF 310, a MAC frame reception unit 320, a MAC frame generation unit 330, a beacon transmission unit 350, and a connection control unit 360. And a learning frame generation unit 380. In FIG. 9, the same reference numerals as those in FIG. 1 are given to the same configurations as those in the first embodiment. In FIG. 1, the wireless base station (a) 120a to the wireless base station (e) 120e are replaced with the wireless base station (a) 122a to the wireless base station (e) 122e, respectively.

  The radio base station (AP) 122 shown in FIG. 9 is different from the radio base station (AP) 120 shown in FIG. 2 in that a learning frame generation unit 380 is provided instead of the boundary registration unit 340. Here, the learning frame generation unit 380 is a functional unit that generates a learning frame for learning the routing of the wired network.

  Next, L2SW routing switching operation at the time of handover in the wireless communication system according to the fourth embodiment will be described. Here, a case is considered where a plurality of radio base stations (AP) 122 are accommodated in the same subnet, and the radio terminal station (STA) 130 performs handover between the radio base stations (AP) 122 in the same subnet. When the wireless terminal station (STA) 130 moves from the communication area of the wireless base station (c) 122c to the communication area of the wireless base station (d) 122d, the wireless terminal station (STA) 130 is configured as a standard handover as standard. Perform the action. The wireless terminal station (STA) 130 disconnects from the wireless base station (c) 122c under a predetermined condition, and reconnects to the wireless base station (d) 122d. At this time, when only the data signal in the direction from the terminal station 110a on the wired network to the wireless terminal station (STA) 130 flows, the L2SW (b) 140b transmits the signal from the terminal station 110a to the wireless base station (c ) Transfer to 122c side.

  Therefore, in the radio base station (d) 122d, the connection control unit 360 detects that the radio terminal station (STA) 130 is connected to the own station, and notifies the learning frame generation unit 380 of it. The learning frame generation unit 380 generates a learning frame with the MAC address of the wireless terminal station (STA) 130 for learning by the L2SW as a transmission source and destined for the foreign agent (b) 150b in the subnet, and the network IF 310 To the foreign agent (b) 150b.

  In the L2SW (b) 140b, the frame of the MAC address of the wireless terminal station (STA) 130, which has been learned under the port to which the wireless base station (c) 122c is connected, is stored in the wireless base station (d) 120d. Input from connected port. Therefore, the L2SW (b) 140b switches the learning of the MAC address of the wireless terminal station (STA) 130 to the wireless base station (d) 122d. After this switching, the data signal in the direction from the terminal station 110a to the wireless terminal station (STA) 130 is sent to the port to which the wireless base station (d) 122d is connected. Therefore, the L2SW (b) 140b transfers the signal from the terminal station 110a to the radio base station (d) 122d, and the signal is transferred to the radio base station (STA) 130 via the radio terminal station (d) 122d. Is done.

  By performing the operation as described above, in the wireless communication system according to the present embodiment, the wireless terminal station (STA) 130 moves within the same subnet, and the downlink signal, that is, wirelessly transmitted from the terminal station 110a. Even when there is only a signal directed to the terminal station (STA) 130, it is possible to normally switch the routing of the L2SW at the time of handover. Thereby, in the radio | wireless communications system concerning this Embodiment, it is possible to transmit data reliably to the radio | wireless terminal station (STA) 130 also on the above conditions. Therefore, in the wireless communication system according to the present embodiment, even when a wireless LAN is applied to a high-speed moving environment, handover processing can be executed in a short time, and the instantaneous interruption time of user data during handover within the same subnet is reduced. It is possible to increase the speed of handover.

  The wireless terminal station (STA) 130 may have a bridge function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, the handover destination radio base station (AP) 120 sends a learning frame to the foreign agent 150 for each MAC address under the radio terminal station (STA) 130. Thereby, the effect similar to said case can be acquired.

  A method for the handover destination AP to know the address of a terminal under the wireless terminal station (STA) 130 is a method of collecting from the wireless terminal station (STA) 130 when connected to the wireless terminal station (STA) 130, or A method of collecting information by exchanging information with the handover destination AP is conceivable.

  The wireless terminal station (STA) 130 may have a router function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, a learning frame is transmitted to the foreign agent (b) 150b with an address represented by the router. Thereby, the effect similar to said case can be acquired.

Embodiment 5. FIG.
In the fifth embodiment, another example of a technique for speeding up handover within the same subnet will be described.

  The basic configuration of the radio communication system and the configuration and function of the radio terminal station (STA) in the present embodiment are the same as those in the first embodiment. Therefore, as for these, referring to the description in FIGS. 1 and 3 and the first embodiment, the detailed description is omitted here. As the radio base station, a radio base station having a conventional configuration that does not have the boundary registration unit 340 in the configuration shown in FIG. 2 (referred to as a radio base station (AP) 123) is used. In FIG. 1, the wireless base station (a) 120a to the wireless base station (e) 120e are replaced with the wireless base station (a) 123a to the wireless base station (e) 123e, respectively.

  Hereinafter, the operation of the radio communication system according to the present embodiment will be described. As shown in FIG. 1, the wireless base station (c) 123 and the wireless base station (d) 123d are accommodated in the same subnet, and the wireless terminal station (STA) 130 is between the wireless base stations (AP) in the same subnet. Consider the case of performing handover. When the wireless terminal station (STA) 130 moves from the communication area of the wireless base station (c) 123c to the communication area of the wireless base station (d) 123d, the wireless terminal station (STA) 130 performs a general handover operation as standard. I do. The wireless terminal station (STA) 130 disconnects from the wireless base station (c) 123c under a predetermined condition, and reconnects to the wireless base station (d) 123d. At this time, when only the data signal in the direction from the terminal station 110a on the wired network to the wireless terminal station (STA) 130 flows, the L2SW (b) 140b transmits the signal from the terminal station 110a to the wireless base station (c ) Transfer to 123c side.

  Therefore, in the wireless terminal station (STA) 130, the connection control unit 460 notifies the registration frame generation unit 410 that the connection with the wireless base station (d) 123d has been completed. The registration frame generation unit 410 generates a registration frame having the MAC address of the wireless terminal station (STA) 130 for learning by the L2SW as a transmission source and destined for the foreign agent (b) 150b in the subnet. The data is sent to the foreign agent (b) 150b via the frame generation unit 420 and the wireless LAN PHY unit 400.

  In the L2SW (b) 140b, the registration frame of the MAC address of the wireless terminal station (STA) 130 that has been learned under the port connected to the wireless base station (c) 122c until now is the wireless base station (d) 120d. Is input from the connected port. Therefore, the L2SW (b) 140b switches the learning of the MAC address of the wireless terminal station (STA) 130 to the wireless base station (d) 122d. After this switching, the data signal in the direction from the terminal station 110a to the wireless terminal station (STA) 130 is sent to the port to which the wireless base station (d) 122d is connected. Therefore, the L2SW (b) 140b transfers the signal from the terminal station 110a to the radio base station (d) 122d, and the signal is transferred to the radio base station (STA) 130 via the radio terminal station (d) 122d. Is done.

  By performing the operation as described above, in the wireless communication system according to the present embodiment, the wireless terminal station (STA) 130 moves within the same subnet, and the downlink signal, that is, wirelessly transmitted from the terminal station 110a. Even when there is only a signal directed to the terminal station (STA) 130, it is possible to normally switch the routing of the L2SW at the time of handover. Thereby, in the radio | wireless communications system concerning this Embodiment, it is possible to transmit data reliably to the radio | wireless terminal station (STA) 130 also on the above conditions. Therefore, in the wireless communication system according to the present embodiment, even when a wireless LAN is applied to a high-speed moving environment, handover processing can be executed in a short time, and the instantaneous interruption time of user data during handover within the same subnet is reduced. It is possible to increase the speed of handover.

  The wireless terminal station (STA) 130 may have a bridge function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, since the wireless terminal station (STA) 130 knows the MAC addresses of the terminals under the wireless terminal station (STA) 130, a learning frame is transmitted to the foreign agent (b) 150b for each MAC address. To do. Thereby, the effect similar to said case can be acquired.

  The wireless terminal station (STA) 130 may have a router function, and a plurality of terminals may exist under the wireless terminal station (STA) 130. In this case, a learning frame is transmitted to the foreign agent (b) 150b with an address represented by the router. Thereby, the effect similar to said case can be acquired.

Embodiment 6 FIG.
In actual use of a wireless communication system, a network in which a plurality of subnets are connected by a router as shown in FIG. 1 is common. Therefore, a method for speeding up handover across subnets as described in the first to third embodiments, and a method for speeding up handover within the same subnet as described in the fourth and fifth embodiments, , May be combined in any combination to form a handover. As a result, it is possible to increase the speed of handover in both cases of handover across subnets and handover within subnets.

  As described above, the handover method according to the present invention is a wireless communication system in which a plurality of wireless base stations distributed and accommodated in a plurality of subnets are arranged two-dimensionally and linearly, and movement control between subnets is performed by mobile IP. In particular, it is suitable for use in a high-speed moving environment.

1 is a diagram showing a system configuration of a wireless LAN system that is a wireless communication system according to a first exemplary embodiment; It is a block diagram which shows the internal function of a wireless base station (AP). It is a block diagram which shows the internal function of a radio | wireless terminal station (STA). 3 is a flowchart for explaining characteristic processing when a wireless LAN system according to the first embodiment is constructed; 3 is a flowchart illustrating an operation of the wireless LAN system according to the first exemplary embodiment. 10 is a flowchart illustrating an operation of the wireless LAN system according to the second exemplary embodiment. FIG. 9 is a configuration diagram showing internal functions of a radio base station (AP) according to a third embodiment; 10 is a flowchart illustrating an operation of the wireless LAN system according to the third exemplary embodiment. FIG. 10 is a configuration diagram showing an internal function of a radio base station (AP) in the fourth embodiment.

Explanation of symbols

100 Core network 110a Terminal station 120a Wireless base station (a)
120b Wireless base station (b)
120c radio base station (c)
120d radio base station (d)
120e Radio base station (e)
130 Wireless terminal station 140a L2SW (a)
140b L2SW (b)
150a Foreign Agent (a)
150b Foreign Agent (b)
160 Home Agent 300 Wireless LAN PHY Unit 310 Network IF
320 MAC frame reception unit 330 MAC frame generation unit 340 boundary registration unit 350 beacon transmission unit 360 connection control unit 370 router advertisement reception unit 380 learning frame generation unit 400 wireless LAN PHY unit 410 network IF
420 MAC frame generation unit 430 MAC frame reception unit 440 Beacon processing unit 450 Registration frame generation unit 460 Connection control unit

Claims (11)

Core a subnet in which a plurality of wireless base stations that perform wireless communication with a wireless terminal station that can move between subnets by mobile IP control and a router device that transfers data packets transferred through the wireless base station are installed A handover method in a wireless communication system that is interconnected via a network,
When the wireless terminal station exists in the visited subnet, the boundary wireless base station at the boundary of the subnet registers boundary information indicating that the own station is located at the boundary of the subnet. Steps,
The boundary radio base station sets the boundary information in a transmission frame and transmits it to a radio terminal station accommodated in the boundary radio base station;
Storing the boundary information when the wireless terminal station receives the transmission frame and determines that the local station is located at the boundary of the subnet based on the presence or absence of the boundary information;
A wireless terminal station storing the boundary information handing over to a different subnet;
The wireless terminal station handed over to the different subnet establishes a connection with the wireless base station in which the local station is accommodated in the handover destination subnet;
A wireless terminal station that establishes a connection with the handover destination wireless base station, and transmits a location registration request of the local station to a host having a home agent function existing in a home network of the wireless terminal station;
The host that has received the location registration request performs a location registration process;
A handover method comprising:   The handover method according to claim 1, wherein the transmission frame is a beacon or a probe response frame. Core a subnet in which a plurality of wireless base stations that perform wireless communication with a wireless terminal station that can move between subnets by mobile IP control and a router device that transfers data packets transferred through the wireless base station are installed A handover method in a wireless communication system that is interconnected via a network,
When the wireless terminal station exists in the visited subnet, the boundary wireless base station at the boundary of the subnet registers boundary information indicating that the own station is located at the boundary of the subnet. Steps,
The boundary radio base station sets the boundary information and address information of a radio base station that is a handover destination of the radio terminal station in a transmission frame and transmits the transmission frame to a radio terminal station accommodated in the boundary radio base station Steps,
Storing the boundary information and address information when the wireless terminal station receives the transmission frame and determines that the local station is located at a boundary portion of the subnet by the presence or absence of the boundary information;
A wireless terminal station storing the boundary information handing over to a different subnet;
A wireless base station that is a handover destination of the wireless terminal station, and sets the address information of the local station in a transmission frame and transmits it to the wireless terminal station;
When the hand-over radio terminal station receives a transmission frame from the handover-destination radio base station and the address information set in the transmission frame matches the stored address information, the position of the local station Sending a registration request to a host with a home agent function present in the home network of the wireless terminal station;
The host that has received the location registration request performs a location registration process;
A handover method comprising:   The handover method according to claim 3, wherein the transmission frame is a beacon or a probe response frame. Core a subnet in which a plurality of wireless base stations that perform wireless communication with a wireless terminal station that can move between subnets by mobile IP control and a router device that transfers data packets transferred through the wireless base station are installed A handover method in a wireless communication system that is interconnected via a network,
When the wireless terminal station exists in a visited subnet, a host having a foreign agent function existing in the subnet transmits an agent advertisement of the own device to a wireless base station under the subnet. When,
The wireless base station receives the agent advertisement, sets the content of the agent advertisement in a beacon or a probe response, and transmits to the wireless terminal station accommodated in the wireless base station;
The wireless terminal station receiving and storing the beacon or probe response;
A wireless terminal station storing the boundary information handing over to a different subnet;
The wireless terminal station that has been handed over establishes a connection with a wireless base station that is accommodated in the handover destination subnet;
A host having a foreign agent function existing in the different subnet transmits an agent advertisement of the own device to a radio base station under the subnet;
The handover-destination radio base station receives the agent advertisement, sets the content of the agent advertisement in a beacon or a probe response, and transmits it to a radio terminal station accommodated in the radio base station;
The handed over wireless terminal station receives a beacon or probe response from the handover destination wireless base station, and the content of the agent advertisement set in the beacon or probe response matches the stored content of the agent advertisement. If not, transmitting the location registration request of the local station to a host having a home agent function existing in the home network of the wireless terminal station;
The host that has received the location registration request performs a location registration process;
A handover method comprising: Subnet in which a plurality of radio base stations that perform radio communication with radio terminal stations that can move between subnets by mobile IP control are installed, and a layer 2 switch device that transfers data packets transferred through the radio base stations is installed A handover method in a wireless communication system connected to a core network,
The wireless terminal station handing over from a subordinate of a first radio base station in a visited subnet to a subordinate of a second radio base station in the subnet;
The handed over wireless terminal station establishing a connection with the second wireless base station;
When the second radio base station detects the establishment of a connection with the handed over radio terminal station, the address of the handed over radio terminal station is used as the transmission source in the subnet upstream of the host. Generating and transmitting a frame destined for a host having an agent function;
The layer 2 switch device existing between the foreign agent and the second radio base station receives the frame transmitted by the second radio base station, and the radio terminal station receives the frame from an input port of the frame. Detecting a handover and learning routing related to the wireless terminal station;
A handover method comprising: Subnet in which a plurality of radio base stations that perform radio communication with radio terminal stations that can move between subnets by mobile IP control are installed, and a layer 2 switch device that transfers data packets transferred through the radio base stations is installed A handover method in a wireless communication system connected to a core network,
The wireless terminal station handing over from a subordinate of a first radio base station in a visited subnet to a subordinate of a second radio base station in the subnet;
The handed over wireless terminal station establishing a connection with the second wireless base station;
The hand-over radio terminal station generates and transmits a frame addressed to a host having a foreign agent function existing upstream of the host in the subnet with the address of the local station as a transmission source;
The layer 2 switch device existing between the foreign agent and the second radio base station receives the frame transmitted by the second radio base station, and the radio terminal station receives the frame from an input port of the frame. Detecting a handover and learning routing related to the wireless terminal station;
A handover method comprising: Boundary registration means for registering boundary information that the own radio base station is a boundary radio base station located at a boundary portion of a subnet where the own radio base station exists;
Beacon sending means for generating a beacon including the radio base station information of the own radio base station and the boundary information and sending it to the radio terminal station;
Connection control means for performing connection processing and handover processing with the wireless terminal station;
A radio base station comprising: An agent advertisement receiving means for receiving an agent advertisement from the outside;
Beacon sending means for generating a beacon including the contents of the wireless base station information of the own station and the agent advertisement and sending it to the wireless terminal station;
Connection control means for performing connection processing and handover processing with the wireless terminal station;
A radio base station comprising: Connection control means for performing connection processing and handover processing with a wireless terminal station;
A learning frame generating unit that receives notification of completion of connection with the wireless terminal station from the connection control unit, generates a learning frame for learning routing of the wired network,
A radio base station comprising: A connection control means for performing a handover process, a connection process with a radio base station, and a connection completion notification process;
Beacon processing means for determining whether the local station is located at the boundary of the subnet from the beacon from the outside, and notifying the determination result and the content of the beacon to the connection control unit;
A registration frame generating means for receiving a notification of completion of connection with the radio base station from the connection control means, and generating and sending a position registration frame for the position registration of the own station;
A wireless terminal station comprising:

Images