JP2000078147A - Radio packet transfer method and radio base station using this method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the radio packet transfer method that can transfer packets without passing through a redundant transfer path so as to prevent the throughput from being decreased, and to provide the radio base station using this method. SOLUTION: A packet monitor section 1 of each radio base station monitors a packet that is transferred on a tree transfer path in a direction of approaching its own station, and a radio terminal denoted by a sender address of the packet and the radio base station denoting a transmission station address are registered in a table 2 in cross-reference. In the case of receiving the packet from a radio terminal belonging to its own station or from the radio base station on a tree transfer path placed in an opposite direction to a route station when viewing from its own station, a packet transfer section 3 references the table 2 to select the radio base station in cross reference to the destination radio terminal as a forwarding transfer destination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless packet transfer method in a wireless packet communication network and a wireless base station using the method.

[0002]

2. Description of the Related Art As a prior art 1 of a packet transfer method,
References “ISO / IEC 10038, ANSI / IEEE Std802.1D,“ Informa
tion technology-Telecommunications and informati
on exchange between systems-Local area networks
-As disclosed in Media Access Control (MAC) bridges ", 1993", there is a transfer method using a spanning tree protocol.

[0003] According to this method, path costs (Pathcosts) are set in advance for all wireless base stations (APs), and one specific wireless base station is set as a root station. here,
The sum of the path costs of the wireless base stations on the communication path between a certain wireless base station and a root station is called a root path cost.
The root station stores its own MAC (Media Ac
cess Control) periodically transmits a configuration message (Configuration Message) in which an address is set. This configuration message has a root path field, and the root station sets the root path cost field to “0” and transmits the configuration message.

[0004] Immediately after activation, the radio base station receives a configuration message for a predetermined period of time, selects a configuration message with the smallest root path cost from among the plurality of received configuration messages, A communication path is set for the source wireless base station of the selected configuration message.

[0005] The selected configuration
The path cost of the own station is added to the root path cost of the message, the source address is set to the MAC address of the own station, and the configuration message is transmitted.
As described above, the configuration message propagates to all the wireless base stations, and the wireless base stations connect the communication paths in a tree shape starting from the root station.

[0006] According to this method, the wireless base station transfers packets on a communication path (tree-like transfer path) connected in a tree-like manner, thereby enabling packet transfer to all the wireless base stations. Packets are prevented from looping between wireless base stations.

Next, as a prior art 2 of the packet transfer method, a document “ISO / IEC 8802-5,“ Information technology ”
-Local and metropolitan networks-Part 5: Token
ringaccess method and physical layer specification
s ", 1992", there is a transfer method using a source routing protocol.

According to this method, a wireless terminal (STA)
When transmitting a data packet, first, the MA of the destination terminal
The search frame including the C address is broadcast transmitted. The destination terminal that has received the search frame is the transmitting terminal M
Broadcast transmission of the all route search frame to which the AC address is assigned. The radio base station that has received the all-routes search frame writes its own identifier and transfers it to another radio base station.

The transmitting terminal selects the received plurality of all-routes search frames, copies the permutation of the identifier of the wireless terminal written in the selected all-routes search frame as routing information in the header of the data packet, and transmits it. . Upon receiving the data packet, the wireless base station selects the next transfer destination wireless base station based on the routing information indicated in the header of the packet, transfers the data packet, and transfers the data packet to the destination wireless terminal.

Next, a method of ascertaining the position of a wireless base station on a tree-shaped transfer path using a source routing protocol will be considered. In this method, a wireless base station newly connected to a tree-shaped transfer path broadcasts a search frame. Each wireless base station that has received the search frame broadcasts an all-routes search frame. The wireless base station newly connected to the tree-shaped transfer path grasps the position of another wireless base station on the tree-shaped transfer path from the received all-path search frame.

On the other hand, the other radio base stations that have received the search frame are the transmission source radio base station of the search frame, that is, the M of the radio base station newly connected to the tree-shaped transfer path.
Broadcast transmission of a search frame including the AC address. The wireless base station newly connected to the tree-shaped transfer path transmits the full path search frame to each search frame transmitting wireless base station. As described above, the other wireless base stations grasp the position on the tree-shaped transfer path of the wireless base station newly connected to the tree-shaped transfer path.

[0012]

According to the packet transfer method according to the prior art 1 described above, since a transfer path is constructed in a tree shape starting from a root station, for example, as shown in FIG. When configured in a tree shape, the wireless base station AP4 and the wireless base station AP3 can communicate directly, but the wireless base station AP4
The packet transfer from the wireless base station AP3 to the wireless base station
4-AP1-AP2-AP3 ". For this reason, the transfer path becomes redundant, causing problems such as an increase in transfer delay time and a decrease in throughput due to consumption of radio resources.

In FIG. 8, when a packet is transferred from the radio base station AP4 to the radio base station AP3, the transfer packet is transferred to the route "AP4-AP3-AP2-AP1-AP".
4), the same packet is received a plurality of times, or the throughput decreases due to the consumption of radio resources.

Further, according to the packet transfer method according to the prior art 2 described above, since data packets are transferred according to routing information, for example, when a transfer path is configured in a tree shape as shown in FIG. The packet transfer from the wireless base station AP4 to the AP3 is directly transferred via the route "AP4-AP3", so that the transfer packet does not loop. However, all wireless terminals transmitting a packet broadcast and transmit a search frame to obtain individual routing information for each destination wireless terminal, and the destination wireless terminal needs to return and transmit an all-routes search frame and broadcast. In a wireless network having a smaller transmission capacity than a wired network, there is a problem that the influence of a decrease in throughput due to the broadcast transmission of the search frame and the all-routes search frame increases. Further, since the wireless terminal needs to manage the routing information for each destination wireless terminal, there is a problem that the load on the wireless terminal increases.

When the packet transfer method according to the prior art 2 is applied to grasping the position of a wireless base station on a tree-like transfer path, all wireless base stations transmit a search frame, and a new tree-like transfer is performed. The wireless base station connected to the transfer path of (1) broadcasts an all-routes search frame to all other wireless base stations, which causes a problem that the throughput is reduced due to the consumption of wireless resources.

The present invention has been made in view of the above circumstances, and a wireless packet transfer method and method capable of transferring packets without passing through a redundant transfer path and preventing a decrease in throughput. It is an object of the present invention to provide a wireless base station using the same.

[0017]

In order to achieve the above object, the present invention has the following arrangement. That is, a wireless packet transfer method according to claim 1 includes a wireless packet including a plurality of wireless base stations forming a tree-shaped transfer path using a specific wireless base station as a root station and wireless terminals belonging to each wireless base station. A wireless packet transfer method in a communication network, wherein each wireless base station monitors a packet transferred in a direction approaching its own station on the tree-shaped transfer path, and monitors a wireless address indicated by a source address of the packet. Register the terminal and the wireless base station indicated by the transmitting station address in the table in association with each other, and on the tree-shaped transfer path located in the opposite direction to the root station as viewed from the wireless terminal belonging to the own station or the own station. When a packet is received from a wireless base station, the destination wireless terminal indicated by the destination address of the packet is registered on the condition that the destination wireless terminal is registered in the table. A wireless base station associated with a wireless terminal is selected as a transfer destination, a packet is transmitted to the wireless base station selected as the transfer destination by shortcutting the tree-like transfer path, and the tree is transmitted from another wireless base station. When receiving a packet transmitted by shortcutting the transfer path in a tree shape, the wireless base station on the tree-shaped transfer path located in the same direction as the root station as viewed from the own station is not selected as a transfer destination. And

In the above-mentioned prior art 1, the radio base station selects only the adjacent radio base station on the tree-shaped transfer path as the next transfer destination radio base station and transfers the packet. The wireless base station monitors the packet transferred in the direction of the local station, registers the source wireless terminal and the transmitting station wireless base station in the table in association with each other, and stores the tree when the destination wireless terminal is registered in the table. The difference is that a wireless base station that is not adjacent to the wireless base station on the transfer path is selected as the next transfer destination wireless base station and the packet is shortcut-transmitted.

The present invention is directed to a method of simply selecting a wireless base station that is not adjacent on a tree-shaped transfer path as a next transfer destination wireless base station and transferring a packet to the wireless base station. Alternatively, shortcut transmission is performed only when a packet is received from a wireless base station located in the opposite direction to the root station on the tree-like transfer path from the own station, and the wireless base station receiving the shortcut packet transfers the tree-like transfer from the own station. The difference is that the data is not transferred to the radio base station located on the route toward the root station.

Further, while the prior art 2 requires broadcast transmission of a search frame and an all-routes search frame by a wireless terminal, the present invention requires broadcast transmission of a search frame and an all-routes search frame by a wireless terminal. Is different.

According to the present invention, the wireless base station monitoring the packet transferred in the direction of the local station can determine the source wireless terminal under the control of the wireless base station indicated by the transmitting station address or the wireless base station indicated by the transmitting station address. Judgment that it is under the control of the radio base station located in the opposite direction to the station, register it in the table, and when transmitting the packet, if the destination radio terminal is already registered in the table, send a shortcut to the associated radio base station This makes it possible to prevent the packet transfer path from becoming redundant, thereby preventing an increase in transfer delay time and a decrease in throughput.

Further, the radio base station transmits a shortcut only when receiving a packet from a radio base station located in a direction opposite to the root station on the tree-shaped transfer path as viewed from the wireless terminal in which the radio base station is located or its own station. The wireless base station receiving the shortcut packet can prevent the transfer packet from looping by prohibiting the transfer to the wireless base station located in the same direction as the root station on the tree-like transfer path from the viewpoint of the local station. Thus, it is possible to prevent the same packet from being received a plurality of times and to reduce the throughput.

Also, the radio base station monitors the packets transmitted by the other radio base stations, so that the radio terminal can execute the shortcut transmission without transmitting the search frame or the all-routes search frame broadcast before the packet transmission. This makes it possible to prevent a decrease in throughput and an increase in the control load of the wireless terminal due to the broadcast transmission of the search frame between the wireless terminals and the all-routes search frame.

According to a second aspect of the present invention, in the wireless packet transfer method, each of the wireless base stations monitors a packet transferred from another wireless base station by short-cutting the tree-shaped transfer path and transmits the packet to the wireless base station. The wireless terminal indicated by the address and the wireless base station indicated by the transmitting station address are associated with each other and registered in the table.

According to the present invention, in addition to the radio base station monitoring the packet in the direction of the local station, the radio base station monitors the packet transmitted by the shortcut, and determines the source radio terminal under the control of the radio base station indicated by the transmission station address, or Judging that it is under the control of the wireless base station located in the opposite direction to the own station when viewed from the wireless base station indicated by the transmitting station address, registering it in the table, and when transferring the packet, if the destination wireless terminal is already registered in the table, associate Shortcut transmission to the specified radio base station has the effect of preventing a packet transfer path from becoming redundant, and preventing an increase in transfer delay time and a decrease in throughput.

A wireless packet transfer method according to claim 3, wherein each of the wireless base stations monitors a packet transferred from another wireless base station on the tree-like transfer path in a direction approaching the local station, or When monitoring a packet transferred from the wireless base station by shortcut of the tree-shaped transfer path, and when a source wireless terminal of the packet is registered in the table, transmission of the monitored packet is monitored. A first radio base station number required to relay a packet from the radio base station indicated by the station address to the own station according to the tree-shaped transfer path, and a radio registered in the table in association with the transmission source radio terminal. The first wireless base station compares the number of second wireless base stations required for relaying a packet from the base station to the own station according to the tree-shaped transfer path, and The number is characterized in that the radio base station indicated by the transmission station address of the packet to the condition in association with the said sender wireless terminal registers updates the table that is the second radio base station number or more.

According to the present invention, the wireless base station monitoring the packet registers the wireless base station having the longer tree path distance in the shortcut table in association with the wireless terminal of the transmission source, thereby making the transfer route redundant by the shortcut transmission. The reduction amount can be further increased, and an effect that an increase in transfer delay time and a decrease in throughput can be prevented can be obtained.

A wireless packet transfer method according to claim 4, wherein each of said wireless base stations monitors a packet transferred from another wireless base station on the tree-like transfer path in a direction approaching its own station. When monitoring a packet transferred from the wireless base station by shortcut of the tree-shaped transfer path, and when a source wireless terminal of the packet is registered in the table, transmission of the monitored packet is monitored. The wireless base station indicated by the station address is not located between the wireless base station registered in the table and the own station in association with the source wireless terminal on the tree-shaped transfer path, or the transmitting station The monitor is provided on condition that the wireless base station indicated by the address matches the wireless base station registered in the table in association with the source wireless terminal. The radio base station indicated by the transmission station address of the packet in association with the said sender wireless terminal and registers updated in the table.

According to the present invention, the radio base station that has monitored the packet determines that the radio base station indicated by the transmission station address is associated with the transmission source radio terminal in the table on the tree-shaped transfer path. If it is not located between itself and the local station, it is determined that the wireless terminal has moved under the control of another wireless base station, and the table is registered and updated, so that the wireless base station The effect of preventing the shortcut transmission from being continued can be obtained.

In addition, a wireless base station having a longer tree path distance can be registered in a table in association with a source wireless terminal, so that the amount of redundancy reduction of a transfer path by shortcut transmission can be further increased, and the transfer delay time can be increased. An effect is obtained that a decrease in throughput can be prevented.

According to a fifth aspect of the present invention, there is provided a wireless packet transfer method including a plurality of wireless base stations forming a tree-shaped transfer path with a specific wireless base station as a root station, and wireless terminals belonging to each wireless base station. A wireless packet transfer method in a packet communication network, wherein each of the wireless base stations monitors a packet transmitted by a wireless terminal belonging to another wireless base station, and receives the packet from a wireless terminal indicated by a source address of the packet. The radio base station indicated by the station address is registered in a table in association with the radio terminal, or the radio base station on the tree-shaped transfer path located in the opposite direction to the root station as viewed from the radio terminal belonging to the self station or the self station. When a packet is received from the destination wireless terminal, the destination wireless terminal indicated by the destination address of the packet is registered on the condition that the destination wireless terminal is registered in the table. The corresponding wireless base station is selected as a transfer destination, a packet is transmitted to the wireless base station selected as the transfer destination by shortcutting the tree-like transfer path, and the tree-like transfer is performed from another wireless base station. When receiving a packet transmitted by short-cutting a route, a wireless base station on the tree-shaped transfer route located in the same direction as the root station as viewed from the own station is not selected as a transfer destination.

In the prior art 1 described above, the radio base station selects only the adjacent radio base station on the tree-shaped transfer path as the next transfer destination radio base station and transfers the packet. Monitor the packet transmitted by the wireless terminal belonging to another wireless base station, register the destination wireless terminal and the transmitting station wireless base station in association with each other in the table, and if the destination wireless terminal is registered in the table, The difference is that a radio base station that is not adjacent on the tree-shaped transfer path is selected as the next transfer destination radio base station and the packet is shortcut-transmitted.

The present invention also relates to a method of simply selecting a wireless base station that is not adjacent on a tree-shaped transfer path as a next transfer destination wireless base station and transferring a packet to the wireless base station. Alternatively, shortcut transmission is performed only when a packet is received from a wireless base station located in the opposite direction to the root station on the tree-like transfer path from the own station, and the wireless base station receiving the shortcut packet transfers the tree-like transfer from the own station. The difference is that the data is not transferred to the radio base station located on the route toward the root station.

[0034] Further, while the prior art 2 requires broadcast transmission of a search frame and an all-routes search frame by a wireless terminal, the present invention requires broadcast transmission of a search frame and an all-routes search frame by a wireless terminal. Is different.

According to the present invention, a radio base station monitoring a packet transmitted by a radio terminal belonging to another radio base station includes:
The source wireless terminal determines that it is under the wireless base indicated by the transmitting station address, registers it in the table, and when transferring the packet, if the destination wireless terminal is already registered in the table, shortcuts to the associated wireless base station. By transmitting, it becomes possible to prevent the transfer route of the packet from becoming redundant, and it is possible to prevent an increase in transfer delay time and a decrease in throughput.

Further, the radio base station transmits a shortcut only when receiving a packet from a radio terminal that is located in a direction opposite to the root station on the tree-like transfer path as viewed from the wireless terminal in which the radio base station is located or its own station. The receiving wireless base station of the packet can prevent the transfer packet from being looped by prohibiting the transfer to the wireless base station located in the same direction as the root station on the tree-like transfer path as viewed from the own station, It is possible to prevent the same packet from being received a plurality of times and to reduce the throughput.

Further, the radio base station monitors the packets transmitted by the other radio base stations, so that the radio terminal can perform the shortcut transmission without broadcasting the search frame or the all-routes search frame prior to the packet transmission. This makes it possible to prevent a decrease in throughput and an increase in the control load of the wireless terminal due to the broadcast transmission of the search frame between the wireless terminals and the all-routes search frame.

According to a sixth aspect of the present invention, there is provided a wireless packet transfer method including a plurality of wireless base stations forming a tree-shaped transfer path using a specific wireless base station as a root station, and wireless terminals belonging to each wireless base station. A packet radio transfer method in a packet communication network, wherein each radio base station monitors a packet transmitted from another radio base station to a radio terminal, and determines a radio terminal and a transmission station address indicated by a destination address of the packet. The corresponding wireless base station is registered in the table, and a packet is received from a wireless terminal belonging to the own station or a wireless base station on the tree-shaped transfer path located in a direction opposite to the root station as viewed from the own station. if you did this,
The wireless base station corresponding to the destination wireless terminal is selected as a transfer destination on condition that the destination wireless terminal indicated by the destination address of the packet is registered in the table, and the tree-shaped transfer path is shortcut. Transmitting a packet to the wireless base station selected as the transfer destination and receiving a packet transmitted by shortcutting the tree-shaped transfer path from another wireless base station, when the root station is viewed from its own station, The wireless base stations on the tree-shaped transfer path located in the same direction are not selected as transfer destinations.

In the prior art 1 described above, the radio base station selects only the adjacent radio base station on the tree-shaped transfer path as the next transfer destination radio base station and transfers the packet. The radio base station monitors a packet transmitted from another radio base station to a radio terminal under the radio base station, registers the destination radio terminal and the transmission station radio base station in the table in association with each other, and the destination radio terminal is registering in the table. Is different in that a wireless base station that is not adjacent on the tree-shaped transfer path is selected as the next transfer destination wireless base station and the packet is shortcut-transmitted.

The present invention is directed to a method of simply selecting a wireless base station that is not adjacent on a tree-shaped transfer path as a next transfer destination wireless base station and transferring a packet to the wireless base station. Alternatively, shortcut transmission is performed only when a packet is received from a wireless base station located in the opposite direction to the root station on the tree-like transfer path from the own station, and the wireless base station receiving the shortcut packet transfers the tree-like transfer from the own station. The difference is that the data is not transferred to the radio base station located on the route toward the root station.

Further, while the prior art 2 requires the broadcast transmission of the search frame and the all-routes search frame by the wireless terminal, the present invention requires the broadcast transmission of the search frame and the all-routes search frame by the wireless terminal. Is different.

According to the present invention, the radio base station monitoring the packet transmitted from the other radio base station to the radio terminal determines that the destination radio terminal is under the radio base indicated by the transmission station address and registers it in the shortcut table. When the destination wireless terminal is already registered in the shortcut table at the time of packet transfer, by transmitting a shortcut to the associated wireless base station, it is possible to prevent the transfer route of the packet from becoming redundant, and to reduce the transfer delay time. It is possible to prevent an increase and a decrease in throughput.

Further, the radio base station transmits a shortcut only when receiving a packet from a radio base station located in a direction opposite to the root station on the tree-like transfer path as viewed from the wireless terminal in which the wireless base station belongs or its own station. The receiving wireless base station of the present invention can prevent a transfer packet from being looped by prohibiting transfer to a wireless base station located in the same direction as the root station on a tree-like transfer path as viewed from its own station. It is possible to prevent the same packet from being received a plurality of times and to reduce the throughput.

Further, the radio base station monitors the packets transmitted by the other radio base stations, thereby enabling shortcut transmission without broadcasting a search frame or an all-routes search frame. It is possible to prevent a decrease in throughput and an increase in control load on the wireless terminal due to the broadcast transmission of the frame and the all-routes search frame.

A wireless packet transfer method according to claim 7, wherein in each of said wireless base stations, a connection notification packet and a connection notification response packet are defined, and said connection notification packet and said connection notification response packet are routed to a data portion thereof. An information field, wherein the path information field indicates the transfer order of all the wireless base stations that have transferred the packet, and is adjacent on the tree-like transfer path in a wireless base station newly connected to the tree-like transfer path. The connection notification packet is transmitted to the wireless base station, and in the adjacent wireless base station that has received the connection notification packet, on the tree-shaped transfer path of the transmission source wireless base station of the connection notification packet from the path information field Recognize the location, update the tree-like transfer route, and connect the source address of the connection notification packet. The connection notification response packet is transmitted by inputting to the destination address of the notification response packet, and the address of the own station is additionally input to the path information field of the connection notification packet, and the radio base indicated by the transmission station address of the connection notification packet Transfer to all the adjacent wireless base stations on the tree-shaped transfer path except the station, and in the wireless base station receiving the connection notification response packet, the wireless base station of the source wireless base station of the connection notification response packet from the path information field The location on the tree-shaped transfer path is grasped, and the tree-shaped transfer path is updated. If the destination address of the connection notification response packet does not match the address of the own station, the address of the own station is changed to the address of the connection notification response packet. It is characterized in that it is additionally input to the route information field and transferred.

According to the present invention, a radio base station newly connected to a tree-shaped transfer path transmits a connection notification packet having a path information field indicating the history of the radio base station to which the packet has been transferred. In that another radio base station on the received tree-shaped transfer path grasps the position on the tree-shaped transfer path of a radio base station newly connected to the tree-shaped transfer path from the path information field. Different from technology.

According to the present invention, the position of the wireless base station newly connected to the tree-shaped transfer path on the tree-shaped transfer path can be grasped by another wireless base station by the connection notification packet. Since the wireless base station does not transmit the route search frame, the effect of preventing a decrease in throughput and the effect of shortening the time required to grasp the positional relationship can be obtained.

In the wireless packet transfer method according to claim 8, in each of the wireless base stations, a connection addition packet and a route notification packet are defined in a packet transferred between the wireless base stations, and the connection addition packet is The data portion has a connection radio base station field, the connection radio base station field indicates an address of a radio base station newly connected to the transmission source radio base station of the connection addition packet, and the route notification packet includes the data portion thereof. Has a path information table field, the path information table field,
This shows the mutual positional relationship between the wireless base stations on the tree-shaped transfer path that the source wireless base station of the packet has grasped, and the communication path is newly established in the wireless base station connected to the tree-shaped transfer path. The wireless base station that transmits the connection addition packet to the connected wireless base station and receives the connection addition packet having the wireless base station adjacent to the transmission path in a tree-like transfer path as a transmission source of the connection addition packet The path notification packet is transmitted to the wireless base station, and the connection addition packet is transferred to an adjacent wireless base station on a tree-shaped transfer path other than the wireless base station indicated by the transmission station address of the connection notification packet. A wireless base station that has received the connection addition packet having a source other than the wireless base station adjacent to the wireless base station on the transfer path, The station recognizes that the station has connected the communication path with the radio base station indicated by the connection radio base station field of the connection addition packet, updates the tree-shaped transfer path, and updates the radio base indicated by the transmission station address of the connection addition packet. Transfer the connection addition packet to all adjacent wireless base stations on a tree-shaped transfer path excluding the station, and, at the wireless base station receiving the route notification packet, determine a tree of another wireless base station from the route information table field. It is characterized in that a tree-shaped transfer path is updated by grasping a position on the transfer path in a tree shape.

According to the present invention, the radio base station newly connected to the tree-shaped transfer path transmits a connection addition packet including a connection radio base station field indicating, for example, a MAC address of the connection destination radio base station to the connection destination radio base station. The other wireless base station on the tree-shaped transfer path that has transmitted and received this connection addition packet is the source wireless base station, that is, the wireless base station newly connected to the tree-shaped transfer path is the connected wireless base station. Understand that it has connected to the wireless base station indicated by the field,
A radio base station newly connected to the tree-shaped transfer path that has received the path notification packet is different from the conventional art in that the position of the other radio base station on the tree-shaped transfer path is grasped from the path information field. And different.

According to the present invention, the radio base station newly connected to the tree-shaped transfer path can recognize the position of another radio base station on the tree-shaped transfer path by using the path notification packet. Since the transmission of a connection notification response packet from another radio base station is not required, the consumption of radio resources is further suppressed, and the effect of further preventing a decrease in throughput and the effect of further shortening the time required to grasp the positional relationship are obtained. can get.

According to a ninth aspect of the present invention, in each of the wireless base stations, a disconnection notification packet is defined in a packet to be transferred between the wireless base stations, and the disconnection notification packet is transmitted to the data section by the disconnection wireless communication. A base station field, and each wireless base station has a function of detecting a disconnection of a communication path with an adjacent wireless base station on a tree-shaped transfer path, and has a function of detecting a communication path with the adjacent wireless base station. When the disconnection is detected, the address of the adjacent wireless base station is input to the disconnected wireless base station field, and the disconnection notification packet is transmitted to all the wireless base stations on the tree-shaped transfer path, and the disconnection is performed. In the wireless base station that has received the notification packet, the communication path between the wireless base station indicated by the disconnected wireless base station field and the wireless base station that has transmitted the disconnection notification packet is disconnected. And updates the tree-like transfer path to understand that the.

According to the present invention, it is possible to recognize the disconnected wireless base station from the tree-shaped transfer path by using the disconnection notification packet, and to associate the wireless terminal registered in the table with the wireless base station. This has the effect of stopping transmission of shortcuts to.

A wireless packet transfer method according to a tenth aspect is characterized in that, in each of the wireless base stations, a packet transmitted by broadcast is not transmitted by shortcutting a tree-like transfer path. According to the present invention, by not transmitting a broadcast packet by shortcut transmission, it is possible to prevent a packet transmitted by broadcast from being looped and to receive the same packet a plurality of times and to prevent a decrease in throughput.

In the wireless packet transfer method according to the eleventh aspect, in each of the wireless base stations, after a wireless terminal is registered in the table, or after a wireless terminal being registered in the table is updated, a predetermined period is set. When the time has elapsed, the registration of the wireless terminal registered in the table is deleted. According to the present invention, when the wireless terminal ends communication, the registration of the table can be deleted after a predetermined period, and the effect of suppressing the amount of memory required for the table can be obtained.

A wireless base station according to a twelfth aspect is a wireless base station in a wireless packet communication network that configures a tree-shaped transfer path using a specific wireless base station as a root station,
A table for associating and registering a wireless terminal indicated by a source address of a packet and a wireless base station indicated by a transmitting station address, and monitors a packet transferred in a direction approaching the own station on the tree-shaped transfer path. And a monitor unit that associates the wireless terminal indicated by the source address of the packet with the wireless base station indicated by the transmitting station address and registers them in the table, and refers to the table to refer to the wireless station belonging to the own station. A transfer unit for transferring a packet from a terminal or another wireless base station, wherein the transfer unit is configured to transfer the tree-shaped transfer, which is located in a direction opposite to the root station as viewed from the wireless terminal belonging to the own station or the own station. When a packet is received from a wireless base station on the route, the destination wireless terminal indicated by the destination address of the packet is registered on the condition that the destination wireless terminal is registered in the table. A wireless base station associated with the terminal is selected as a transfer destination, a packet is transmitted by shortcutting the tree-shaped transfer path to the wireless base station selected as the transfer destination, and the tree is transmitted from another wireless base station to the tree. When receiving a packet transmitted by shortcutting the transfer path in a tree shape, the wireless base station on the tree-shaped transfer path located in the same direction as the root station as viewed from the own station is not selected as a transfer destination. And

A wireless base station according to a thirteenth aspect is a wireless base station in a wireless packet communication network that configures a tree-shaped transfer path with a specific wireless base station as a root station,
A table for associating and registering the wireless terminal indicated by the source address of the packet and the wireless base station indicated by the receiving station address, and monitoring the packet transmitted by the wireless terminal belonging to another wireless base station, A monitor unit for registering the wireless terminal indicated by the source address of the packet and the wireless base station indicated by the receiving station address in the table, and referring to the table, the wireless terminal belonging to the own station or another wireless terminal; A transfer unit for transferring a packet from a base station, wherein the transfer unit is a wireless terminal belonging to the own station or a wireless terminal on the tree-shaped transfer path located in a direction opposite to the root station as viewed from the own station. When a packet is received from a base station, the destination wireless terminal indicated by the destination address of the packet is associated with the destination wireless terminal on condition that the destination wireless terminal is registered in the table. The selected wireless base station is selected as a transfer destination, a packet is transmitted to the wireless base station selected as the transfer destination by shortcutting the tree-shaped transfer path, and the tree-shaped transfer path is transmitted from another wireless base station. When a packet transmitted as a shortcut is received, a wireless base station on the tree-shaped transfer path located in the same direction as the root station as viewed from the own station is not selected as a transfer destination.

A wireless base station according to claim 14 is a wireless base station in a wireless packet communication network that configures a tree-shaped transfer path with a specific wireless base station as a root station,
A table for associating and registering the wireless terminal indicated by the destination address of the packet and the wireless base station indicated by the transmitting station address, and monitoring a packet transmitted from another wireless base station to the wireless terminal to determine the destination address of the packet A monitor unit that registers the wireless terminal indicated by the transmitting station address and the wireless base station indicated by the transmitting station address in the table, and refers to the table, and transmits a packet from the wireless terminal or another wireless base station belonging to the own station. A transfer unit for transferring, the transfer unit,
When a packet is received from a wireless terminal belonging to the own station or a wireless base station on the tree-shaped transfer path located in a direction opposite to the root station as viewed from the own station, a destination radio indicated by a destination address of the packet A wireless base station associated with the destination wireless terminal is selected as a transfer destination on condition that the terminal is registered in the table, and the tree-shaped transfer path is shortcut to be selected as the transfer destination. When transmitting a packet to a base station and receiving a packet transmitted from another radio base station by shortcut of the tree-shaped transfer path, the tree-shaped transfer located in the same direction as the root station as viewed from the own station. The wireless base station on the route is not selected as a transfer destination.

[0058]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a characteristic portion of a wireless base station AP used in a wireless packet communication network according to this embodiment. The wireless base station AP shown in FIG. 1 is arranged at each node of a wireless packet communication network in which a transfer path is formed in a tree shape by, for example, a spanning tree protocol, and shortcuts the tree-shaped transfer path. This is characterized in that packets are transmitted using

The other functions are the same as those of a normal radio base station. For example, when a packet is received from another wireless base station, or when a packet is received from an associated wireless terminal, when the destination wireless terminal of the packet is belonging to the own station, the packet is transmitted to this terminal. Transfer,
When the destination wireless terminal is not belonging to the own station, the packet is transferred to the next transfer destination wireless base station.

In FIG. 1, a packet monitor 1 (monitor) monitors a packet transferred in a direction approaching its own station on a tree-shaped transfer path, and a radio terminal transmitting the packet and a radio base station Are registered in the shortcut table 2 (table). In the shortcut table 2, the wireless terminal indicated by the source address of the monitored packet (that is, the packet transferred in the direction approaching the own station direction) and the wireless base station indicated by the transmitting station address are registered in association with each other. You.

The packet transfer unit 3 (transfer unit) transfers a packet from a wireless terminal belonging to its own station or another wireless base station. The transfer function has a function of transferring the packet by short-cutting the transfer path in the shape of a circle.
Each wireless base station and each wireless terminal have an apparatus-specific address (MAC address) as an identifier.

FIG. 2 shows a format of a packet transferred in the wireless packet communication network according to this embodiment. As shown in the figure, each packet is composed of a header section for inputting a control signal and a data section for inputting transfer data. The packet A is used for a transfer packet from the wireless terminal to the wireless base station, and includes a header section including “format type”, “receiving station address”, “source address”, “destination address”, and “reserved”. Having.

The packet B is used for packet transfer between radio base stations, and includes "format type", "receiving station address", "transmitting station address",
It has a header section composed of four types of address fields, “destination address” and “source address”. Packet C
Is used for a transfer packet from the wireless base station to the wireless terminal, and has a header portion including “format type”, “destination address”, “transmission station address”, “source address”, and “reserved”. .

Here, the destination address indicates the MAC address of the wireless terminal of the destination of the packet, the source address indicates the MAC address of the wireless terminal of the source of the packet, and the receiving station address indicates the transfer destination (current wireless terminal). MAC of the wireless base station of the wireless base station that receives the packet from the base station)
The transmission station address indicates the MAC address of the wireless base station of the transfer source (the wireless base station transmitting the packet to the current wireless base station).

A connection notification packet and a connection notification response packet, which will be described later when a wireless base station is newly connected to a wireless packet communication network, have a route information field. Starting with the MAC address of the source wireless base station, the MAC address of the wireless base station that relayed the packet is input in the order of relay.

Next, the basic operation of the radio base station according to this embodiment will be described with reference to FIGS. 3 to 6 by taking as an example a radio packet communication network forming a tree-like transfer path shown in FIGS. The description will be given along the flowchart shown. Here, in FIG. 7, a transfer path is not set between the radio base stations AP3 and AP7, the radio base stations AP3 and AP4, and the radio base stations AP3 and AP6, but a radio wave shield is set between them. No transmission packets can be monitored.

The number of relay radio base stations required for packet transfer between two radio bases on a tree-shaped transfer path is defined as a "tree path distance" between the radio base stations. For example, in FIG. 8, the tree path distance between the wireless base stations AP3 and AP7 is 3, and the wireless base stations AP3 and AP3
The tree path distance to P4 is 2. Also, as viewed from a certain wireless base station, the direction of the root station on the tree-shaped transfer route is defined as an upper direction, and the opposite direction is defined as a lower direction.

Hereinafter, the basic operation of each radio base station will be described. In the following basic operation, the operation of monitoring a packet and registering / updating it in the shortcut table 2 is mainly performed by the packet monitor unit 1, and the operation of determining the transfer destination with reference to the shortcut table 2 is mainly performed by the packet monitor unit. This is performed by the transfer unit 3. For other various control / judgment operations,
It is realized by functions other than the packet monitoring unit 1 and the packet transfer unit 3. However, these functions (basic operations) do not necessarily have to be assigned as the functions of the packet monitor 1 and the packet transfer unit 3, and may be realized on software as the functions of the radio base station.

(Basic Operation 1) Each radio base station receives a packet transmitted by a surrounding radio base station,
Is monitored (step S01). Here, packet B
Is monitored (step S02: YES), the wireless base station (transmitting station A) indicated by the transmitting station address of this packet
P) is not an adjacent wireless base station on the tree-shaped transfer path (step S03: NO), and this packet B is a packet to be transferred toward the own station (own station direction packet) (step S04: YES) If the source wireless terminal has not been registered (step S05: NO), the source wireless base station is registered in the shortcut table 2 in association with the transmitting station AP of the packet (see claims 1 and 12). Start the registration suspension timer (step S0
6). However, when the transmitting station AP is an adjacent wireless base station on the tree-shaped transfer path (step S03: YE
Do not register in S).

(Basic Operation 2) Each radio base station is in the case where the transmitting station AP of the packet B and the radio base station (receiving station AP) indicated by the receiving station address are not adjacent to each other on the tree-shaped transfer path. If the packet is not a packet directed to the own station (step S04: NO), it is determined that the packet is a shortcut transmitted packet (shortcut packet) (step S07: YES).

At this time, the source wireless terminal (source ST)
If A) is not registered (step S05: NO), the transmission source STA is registered in the shortcut table 2 in association with the transmission station AP (see claim 2). However, the transmitting station AP
Is not registered when is a wireless base station adjacent on the tree-like transfer path. At the time of registration of the shortcut table, a registration suspension timer is started.

(Basic Operation 3) When the transmission source STA is registered in the shortcut table 2 (step S05: YES), each wireless base station determines a tree path distance between the local station and the transmission station AP (the first path distance). When the number of wireless base stations is equal to or greater than the tree path distance (the number of second wireless base stations) between the own station and the wireless base station associated with the registered wireless terminal (step S08: YES) , The associated wireless base station is registered and updated as the transmitting station AP (step S0).
9) (see claim 3). When the registration is updated, the registration suspension timer is restarted.

(Basic Operation 4) In each wireless base station, the transmitting station AP transmits a tree-shaped transfer path between the wireless base station associated with the wireless terminal registered in the shortcut table 2 and the own station. If the wireless base station is not located in the wireless terminal or coincides with the wireless base station associated with the registered wireless terminal (registered STA) (step S08: YES), the associated wireless base station is registered in the transmitting station AP. Update (step S09) (refer to claim 4). When the registration is updated, the registration suspension timer is restarted. Note that the above-described basic operation 3 and basic operation 4 are not performed simultaneously, and one of them is selected in advance.

(Basic Operation 5) Each wireless base station monitors a packet C transmitted by a surrounding AP (step S0).
1: NO to step S10: YES), the destination wireless terminal (destination STA) and the transmitting station AP are registered in the shortcut table 2 (steps S11 to S13).
14). However, when the transmitting station AP is an adjacent wireless base station on the tree-shaped transfer path (step S11: YE
Do not register in S). If the destination STA has been registered (step S12: YES), the shortcut table 2
Is updated (step S14), and the registration suspension timer is restarted.

(Basic Operation 6) Each radio base station monitors the packet A transmitted by the surrounding radio terminals (step S).
01: NO to step S10: NO), the source STA and the receiving station AP are registered in the shortcut table 2 (steps S20 to S23) (see claims 5 and 13). However, if the receiving station AP is an adjacent wireless base station on the tree-shaped transfer path (step S21: YES), no registration is performed. When the source STA has been registered (step S22:
In the case of YES), the registration of the shortcut table 2 is updated (step S24), and the registration suspension timer is restarted.

(Basic Operation 7) When the receiving station AP is its own station (step S30: YES), and when the received packet is a broadcast packet (step S31: YES), each radio base station broadcasts to the wireless terminal to which it belongs. At the same time as transmitting, the packet B is sequentially transferred to all the adjacent wireless base stations on the tree-shaped transfer path excluding the transmitting station AP of the received packet as the receiving station AP (step S3).
2). However, in this case, the transfer by the shortcut is not performed (see claim 10). This prevents a packet transmitted by broadcast from looping on the path. (Basic operation 8) When the destination STA is a wireless terminal belonging to its own station, each wireless base station (step S33:
YES), the packet A is transmitted to the destination STA (step S34) (common to all claims).

(Basic Operation 9) When each wireless base station receives the packet A from the wireless terminal belonging to it (step S3).
5: YES) or a lower-direction radio base station (lower-order A
P) when packet B is received (step S36: Y
ES), if the destination STA is being registered in the shortcut table 2 (step S37: YES), the packet B is shortcut-transmitted to the associated wireless base station as the receiving station AP (step S3).
8). If not registered (step S37: NO), the packet B is sequentially transferred to all adjacent wireless base stations on the tree-shaped transfer path excluding the transmitting station AP (step S39) (common to all claims).

(Basic Operation 10) When each radio base station receives a shortcut packet (step S40:
YES), the packet B is transferred to the wireless base station (lower AP) in the lower direction (step S41) (common to all claims).
At this time, since no packet is transferred to the upper AP, the occurrence of a loop is prevented. (Basic operation 11) Wireless base station in upper direction (upper AP)
, When the received packet is not a shortcut packet (step S4).
0: NO), the packet B is sequentially transferred to all adjacent wireless base stations on the tree-shaped transfer path excluding the transmitting station AP (step S42). At this time, since the received packet from the upper AP is not transferred by the shortcut, the occurrence of the loop is prevented.

(Basic Operation 12) Each wireless base station has a registration hold corresponding to each wireless terminal registered in the shortcut table 1 on a one-to-one basis, and a continuous packet for updating the registration of each wireless terminal. Measure unreceived time. Each wireless base station measures a continuous non-reception time by a registration hold timer, and after a certain wireless terminal is registered, a predetermined time elapses without registration update of the wireless terminal, and a registration hold timer Has expired (step S50), the registration of the wireless terminal (corresponding STA) is deleted from the shortcut table 2 (step S50).
51) (see claim 11).

Each radio base station connects / disconnects a communication path to / from a radio packet communication network composed of a tree-shaped transfer path.
The following basic operation is performed for disconnection. (Basic operation 13) Each wireless base station defines a connection notification packet and a connection notification response packet, and when newly connecting to a tree-shaped transfer path, inputs the transfer order of the wireless base stations in the connection notification packet and creates a tree. Inform the other wireless base station of the position of the own station on the transfer path of the shape, and when receiving the connection notification packet, input the source address of the connection notification packet into the destination address of the connection notification response packet, and The position is notified to another wireless base station (see claim 7).

(Basic Operation 14) Each radio base station defines a connection addition packet indicating an address of a newly connected radio base station and a route notification packet indicating a mutual positional relationship between the radio base stations, and When the connection addition packet is transmitted to the wireless base station to which the connection has been connected and transferred to each of the other wireless base stations, and when the path addition packet is received, a route notification packet is transmitted to the source base station of the connection addition packet. The position of the own station is notified (see claim 8).

(Basic Operation 15) Each wireless base station has a function of detecting a disconnection of a communication path with an adjacent wireless base station on a tree-shaped transfer path, and converts a packet transferred between wireless base stations into a communication path. Is defined, a disconnection notification packet indicating that the packet has been disconnected is defined, and the disconnection notification packet is transmitted to all wireless base stations on the tree-shaped transfer path. It is grasped that the communication path has been disconnected (see claim 9).

Next, an example of the configuration of a wireless packet communication network using the wireless base stations having the above-described basic operations and the operation of each wireless base station will be described. FIG. 7 shows an example of the arrangement of wireless base stations according to this embodiment. In the figure, the wireless terminal STA
1 belongs to the wireless base station AP1, the wireless terminal STA3 belongs to the wireless base station AP3, the wireless terminal STA5 belongs to the wireless base station AP5, and the wireless terminal STA6 belongs to the wireless base station AP.
6 and the wireless terminal STA7 belongs to the wireless base station AP7. Also, in the figure, the hatched figure portion represents a radio wave shield, and is an area where a transfer route between wireless base stations is not set.

In general, wireless L such as a wireless packet communication network
In the AN, each wireless base station (AP) periodically transmits a beacon signal to which its own MAC address is assigned in its own cell. Each wireless terminal (STA) transmits a beacon signal source AP.
Send the attribution signal to. Upon receiving this, the wireless base station determines that the transmission source STA of the belonging signal is belonging, and performs transmission of a packet to the wireless terminal in the belonging and reception / transfer of a packet from the wireless terminal. Each wireless base station may notify the wireless terminal of the completion of the assignment for improving the reliability.

When configuring a wireless packet communication network, each wireless base station sets a specific wireless base station as a root station and sets a tree-like transfer path by, for example, a spanning tree protocol. However, in FIG. 7, the root station is the wireless base station AP1, and the path costs of each wireless base station are all the same value. Subsequently, each wireless base station grasps the position of the other wireless base station on the tree-shaped transfer path,
Build information about the transfer route.

Here, in FIG. 7, the radio base station AP7
Is newly connected to a tree-shaped transfer path, and a case where the above-described basic operation 13 (refer to claim 7) is used as a method of constructing information on the transfer path will be described. In this case, the wireless base station AP7 is
A connection notification packet for notifying that connection has been made to the base station AP4 is transmitted to the wireless base station AP4. Upon receiving this, the radio base station AP4 transmits a connection notification response packet for notifying that the connection notification packet has been received to the radio base station AP7, and also sets its own MAC address in the path information field of the connection notification packet. By additionally inputting, the connection notification packet is transferred to the adjacent wireless base stations AP1 and AP6.

[0086] The same is transferred in the same manner as above, and the radio base station AP7 is transferred.
Are transmitted to all the radio base stations, and upon receiving this, each radio base station transmits a connection notification response packet to the radio base station AP7. As a result, for example, the route information field of the connection notification packet received by the wireless base station AP5 includes the wireless base stations AP7, AP4,.
The MAC addresses of P1, AP2, and AP3 are sequentially input. Also, the newly connected wireless base station AP7 is
The position of each wireless base station on the tree-shaped transfer path is known from the connection notification response packet from another wireless base station.
Further, the other wireless base stations know the position of the wireless base station AP7 from the connection notification packet. FIG. 8 shows a final tree-shaped transfer route set by each radio base station shown in FIG. 7 using the spanning tree protocol.

Next, in FIG. 7, another construction method of the information on the transfer path when the radio base station AP7 is newly connected to the tree-shaped transfer path (radio base station 4) (see claim 8). The case where the above-described basic operation 14 is used will be described. According to this method, the radio base station AP7
Transmits to the wireless base station AP4 a connection addition packet indicating that the wireless base station AP4 has been additionally connected. Upon receiving this, the wireless base station AP4 transfers the connection addition packet to the adjacent wireless base stations AP1 and AP6, and transmits a route notification packet to the wireless base station AP7.

The connection addition packet transmitted from the wireless base station AP7 is transferred to all the wireless base stations, and the other wireless base stations receiving the connection addition packet communicate between the wireless base station AP7 and the wireless base station AP4. Know that you have connected the road. The wireless base station AP7 knows the position of another wireless base station on the tree-shaped transfer path from the path information table field of the path notification packet. This path information table field is represented as a list of MAC addresses of the respective radio base stations starting from the transmission source radio base station of the path information table packet. For example, the route information table field transmitted by the wireless base station AP4 is (AP4, AP4
6) (AP4, AP1, AP2, AP3, AP5).

Hereinafter, as an operation of the radio base station according to this embodiment, an operation when a packet is transferred by shortcutting a transfer path in a radio packet communication network (tree-shaped transfer path) shown in FIG. 8 will be described. . FIG. 9 shows a transmission example 1 in which the communication between the wireless terminals STA7 and STA3 is transmitted as an example and a packet is transmitted by shortcutting a tree-shaped transfer path. However, it is assumed that no wireless terminal is registered in the shortcut table 2 of all wireless base stations in the initial state.

First, the wireless terminal STA7 is
A case where a packet is transmitted to address 3 will be described. Wireless terminal S
When a packet addressed to the wireless terminal STA3 is transmitted from the TA7, the wireless base station AP7 to which the wireless terminal STA7 belongs becomes:
When receiving the packet A from the wireless terminal STA7, since the destination wireless terminal STA3 is not belonging and the wireless terminal STA3 has not been registered in the shortcut table 2, the packet is transferred to the adjacent wireless base station AP4 via the tree-shaped transfer path. I do. The wireless base station AP3 monitors the packet B transmitted by the wireless base station AP7, and the transfer direction of the packet transferred from the wireless base station AP7 to AP1 is the own station direction.
The source wireless terminal STA7 and the wireless base station A as the transmitting station
P7 is registered in the shortcut table 2, and a registration suspension timer is started.

Since the wireless base station AP4 also has no wireless terminal STA3 and is not registered in the shortcut table, the wireless base station AP4 transfers the packet to the adjacent wireless base stations AP1 and AP6 via a tree-like transfer route. The wireless base station AP3 monitors the packet transmitted by the wireless base station AP4, and the packet transferred from the wireless base station AP4 to the AP1 is directed to its own station, but the wireless terminal STA7 of the transmission source is registering the shortcut table. And the wireless base station AP4 that is being registered on the tree-shaped transfer path by the wireless base station AP4 that is the transmitting station.
7, the registration of the shortcut table is not updated.

The packet from the wireless base station AP4 is transferred to the wireless base station AP3 via the wireless base stations AP1 and AP2, and the wireless base station AP3 transmits a packet C to the wireless terminal STA3. Wireless base stations AP7, AP4 and AP6
Monitors the packet C transmitted by the wireless base station AP3 to the wireless terminal STA3, associates the destination wireless terminal STA3 with the wireless base station AP3 as the transmitting station, registers the packet in the shortcut table 2, and starts the registration suspension timer. As described above, the packet transmitted from the wireless terminal STA7 is received by the wireless terminal STA3.

Subsequently, a case where the wireless terminal STA3 transmits a packet to the wireless terminal STA7 will be described.
In this case, since the wireless base station AP3 is a packet received from the wireless terminal to which the wireless terminal STA7 is registered in the shortcut table and belongs to, the original tree-shaped transfer path (in this case, AP3-AP2-AP1- AP4-
AP7) is directly transmitted to the wireless base station AP7 by shortcut.

The wireless base station AP7 is in contact with the wireless base station AP3 whose wireless terminal STA3, which is the source of the packet transmitted by the shortcut (shortcut packet), is registering the shortcut table, and whose associated wireless base station is the transmitting station. Since they match, the registration suspension timer is restarted, and packet C is transmitted to wireless terminal STA7. As described above, the packet transmitted from the wireless terminal STA3 is received by the wireless terminal STA7. FIG. 10 shows the wireless base stations AP3, AP4, AP in the transmission example 1 described above.
6 and 7 show the contents of the final shortcut table 2 of AP7.

FIG. 11 shows the wireless terminals STA6 and S
Taking the communication with the TA3 as an example, a transmission example 2 in which a packet is transmitted by shortcutting a tree-shaped transfer path is shown.
However, in the initial state, the radio base stations AP3 and AP
The contents of each of the shortcut tables 2 for AP4, AP6, and AP7 are as shown in FIG. 10, and it is assumed that no wireless terminal is registered in the shortcut tables of the other wireless base stations. Further, the wireless base station AP3 can monitor a packet transmitted by the wireless terminal STA6.

When the packet A is transmitted from the wireless terminal STA6 to the wireless base station AP6, the wireless base station AP3 monitors the packet A and stores the packet A in the shortcut table with the wireless base station AP6 as the receiving station. 2
And starts the registration suspension timer. Upon receiving the packet, the wireless base station AP6 transmits the packet A to the destination terminal S.
Since TA3 is a packet that is registered in the shortcut table 2 and received from the wireless base station to which it belongs, the packet B is shortcut-transmitted to the associated wireless base station AP3.

The radio base station AP3 receiving this packet
Is the wireless terminal STA that is the source of the shortcut packet.
6 is registered in the shortcut table 2 and the associated wireless base station is the wireless base station AP of the transmission source.
6, the registration suspension timer is restarted, and the packet C is transmitted to the wireless terminal STA3. Wireless base station A
P4 and AP6 are the wireless base station AP whose destination wireless terminal STA3 of the packet C is registered in the shortcut table 2 and whose associated wireless base station is the transmitting station.
Since it matches 3, the registration suspension timer is restarted.
As described above, the packet transmitted from the wireless terminal STA6 is received by the wireless terminal STA3.

Subsequently, a case where the wireless terminal STA3 transmits a packet to the wireless terminal STA6 afterwards will be described.
In this case, the wireless base station AP3 is a packet that the wireless terminal STA6 is registering in the shortcut table 2 and received from the wireless terminal to which the wireless terminal STA6 belongs.
6. Shortcut transmission to 6. Wireless base stations AP6 and AP
4 and AP7, the registration suspension timer is set because the wireless terminal STA3, which is the transmission source of the shortcut packet, is being registered in the shortcut table 2 and the associated wireless base station matches the wireless base station AP3 which is the transmitting station. And the wireless base station AP6 transmits the packet C to the wireless terminal STA7. As described above, the wireless terminal STA3
Are received by the wireless terminal STA6. FIG. 12 shows the wireless base station AP in the transmission example 2 described above.
3 shows the contents of the final shortcut tables of AP4, AP7, and AP6.

FIG. 13 shows the wireless terminals STA5 and S
Taking the communication with the TA 6 as an example, a transmission example 3 in which a packet is transmitted by shortcutting the tree-shaped transfer path is shown.
However, in the initial state, the radio base stations AP3 and AP
It is assumed that the contents of the shortcut tables 2 of AP4, AP7, and AP6 are as shown in FIG. 12 described above, and no wireless terminal is registered in the shortcut tables of the other wireless base stations.

When the packet A is transmitted from the wireless terminal STA5 to the wireless terminal STA6, the wireless base station AP5 receiving the packet A determines that the destination terminal STA6 of the packet A is not belonging (not registered in the belonging table), and Since the packet B has not been registered in the shortcut table 2, the packet B is transferred to all adjacent wireless base stations (here, only the wireless base station AP3) along a tree-shaped transfer path.

The wireless base station AP3 receives the packet B
Is received from the wireless base station located in the opposite direction to the root station, and the destination wireless terminal STA6 is registering in the shortcut table 2, so that shortcut transmission to the associated wireless base station AP6 is performed. . Upon receiving the shortcut packet, the wireless base station AP6 registers the wireless terminal STA5 as the transmission source and the wireless base station AP3 as the transmitting station in the shortcut table 2, and starts the registration suspension timer.

Further, the radio base stations AP4 and AP7 monitor the shortcut packet transmitted by the radio base station AP6, register the radio terminal STA6 of the transmission source and the radio base station AP3 as the transmission station in the shortcut table 2, and register them. Start the hold timer. Next, the wireless base station AP6
Transmits the received packet C to the wireless terminal STA6. The wireless base station AP3 monitors this packet C,
Since the destination wireless terminal STA6 is being registered in the shortcut table 2 and the associated wireless base station matches the wireless base station AP6 as the transmitting station, the registration suspension timer is restarted.

Next, the case where the wireless terminal STA6 transmits a packet to the wireless terminal STA5 will be described.
In this case, the wireless base station AP3 monitors the packet A transmitted from the wireless terminal STA6, and
Since A6 is being registered in the shortcut table 2 and the associated wireless base station matches the wireless base station AP6 which is the transmitting station, the registration suspension timer is restarted.

The wireless base station AP6 transmits a shortcut to the associated wireless base station AP3 because the packet is received from the wireless terminal to which the wireless terminal STA5 is registered in the shortcut table 2 and belongs. Upon receiving this, the wireless base station AP3 registers the wireless terminal STA6, which is the transmission source of the shortcut packet, with the wireless base station AP6, which is the transmitting station, in the shortcut table 2, and the associated wireless base station is the transmitting station. , The registration suspension timer is started.

Next, the radio base station AP3 is a radio base station which is an adjacent station in the opposite direction to the root station on the tree-shaped transfer route since the destination radio terminal STA5 is not belonging and has not been registered in the shortcut table 2. Packet B to station AP5
To transfer. As a result, the transfer packet is transferred to the route “AP3
A loop of “→ AP2 → AP1 → AP4 → AP3” is prevented. However, the route “AP4 → AP3” is a route by shortcut transmission.

The radio base stations AP4, AP6 and AP7 monitor the packet B transmitted from the radio base station AP3, but do not do anything because they are not directed to their own station. The wireless base station AP5 that has received the packet transmits the packet C to the wireless terminal STA5. As described above, the packet transmitted from the wireless terminal STA6 is received by the wireless terminal STA5. FIG.
4 shows the wireless base stations AP3 and AP in the transmission example 3 described above.
4 shows the contents of the final shortcut tables of AP7 and AP6.

Next, FIG. 15 shows a transmission example in which a packet is transferred without short-cutting a tree-shaped transfer path by taking communication between the wireless terminals STA1 and STA3 as an example. However, in the initial state, the radio base station AP
It is assumed that the contents of the shortcut tables 3, 3, AP4, AP7, and AP6 are as shown in FIG. 14 described above, and that no wireless terminal is registered in the shortcut tables of the other wireless base stations.

When the packet A addressed to the wireless terminal STA3 is transmitted from the wireless terminal STA1, the wireless base station AP1 receiving the packet A does not belong to the destination wireless terminal STA3.
Further, since the packet is not registered in the shortcut table 2, the packet is transferred to the adjacent wireless base stations AP2 and AP4 on the tree-shaped transfer route. Radio base station AP2 receiving this
Is transferred to the wireless base station AP3, and the wireless base station AP3 transmits to the wireless terminal STA3.

On the other hand, the radio base station AP4 that has received the packet from the radio base station AP1 is the one in which the radio terminal STA3 is registering in the shortcut table 2 but the received packet B is received from the radio base station in the upper direction. Therefore, the transfer by the shortcut to the wireless base station AP3 is not performed. As a result, only one of the packets transferred from the wireless base station AP1 to the wireless base stations AP2 and AP4 is received by the wireless terminal STA3, and the wireless terminal STA3 receives the packet.
3 is prevented from receiving the same packet twice.

Next, FIG. 16 shows an example of an operation (registration update of a shortcut table) when the wireless terminal STA7 belonging to the wireless base station AP7 moves under the control of the wireless base station AP6. The wireless terminal STA7 is a wireless base station AP
6 is transmitted. Wireless base station AP4
Monitors the packet A transmitted by the wireless terminal STA7, the wireless terminal STA7 is registering in the shortcut table, and the wireless base station AP6 which is the receiving station is on the tree-shaped transfer path wireless base station AP7 (registering ) And the own station, the association is changed to the wireless base station AP6, and the registration suspension timer is started.

If the wireless base station AP4 cannot monitor the packet A transmitted from the wireless terminal STA7, it monitors the packet B transmitted from the wireless base station AP6 and changes the association of the shortcut table in the same manner.
FIG. 17 shows the wireless base stations AP3, AP4 and AP4 in this example.
The contents of the final shortcut tables of AP7 and AP6 are shown.

Next, FIG. 18 shows an example in which the wireless terminal STA7 that has moved under the control of the wireless base station AP6 transmits a packet by the broadcast method. When transmitting a packet by broadcast, transmission is not performed by shortcut of the transfer path, and the packet is transferred on a tree-shaped transfer path which is an original transfer path.
That is, in this example, the wireless base station AP6
When a packet is received from TA7, the packet is transferred to the adjacent radio base station AP4.

The radio base station AP4 receiving this transfers the data to the adjacent radio base stations AP1 and AP7. The wireless base station AP1 transfers the packet transferred from the wireless base station AP4 to the wireless base station AP2, the wireless base station AP2 transfers the packet to the wireless base station AP3, and the wireless base station AP3 transfers the packet to the wireless base station AP5. Transfer to As described above, the wireless terminal S
The packet transmitted from TA7 is transferred to all wireless base stations.

Finally, the operation when the tree-shaped transfer path is disconnected will be described. For example, each wireless base station monitors a beacon signal periodically transmitted by an adjacent wireless base station on a tree-shaped transfer path, and when the beacon signal cannot be continuously received N times (N: a predetermined threshold), It is determined that the communication channel with the wireless base station that issues the beacon signal has been disconnected.

For example, in FIG. 7, when an obstacle is generated between the radio base stations AP4 and AP7 and the radio base station AP4 cannot receive a beacon signal from the radio base station AP7, Determines that the communication path with the wireless base station AP7 has been disconnected, and transmits a disconnection notification packet in which the MAC address of the wireless base station AP7 is input to the “disconnected wireless base station field” to the wireless base stations AP6 and AP1. .

The wireless base station AP1 receiving this transfers the wireless base station AP2 to the wireless base station AP2, and similarly transfers the disconnection notification packet to all the wireless base stations. Each wireless base station that has received the disconnection notification packet knows that the communication path between the wireless base stations AP7 and AP4 has been disconnected, and if the wireless terminal registered in the shortcut table is associated with the wireless base station AP7, , Delete the registration and stop sending by shortcut.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and the present invention is included in the present invention even if there is a design change or the like without departing from the gist of the present invention. It is. For example, in the above-described embodiment, each wireless base station has the shortcut table 2. However, this shortcut table may be provided only in a specific plurality of wireless base stations, and the specific wireless base station may include the shortcut table 2. It may be configured such that only the base station can perform shortcut transmission.

[0119]

As described above, according to the present invention, the following effects can be obtained. That is, a packet transferred in a direction approaching the local station on the tree-shaped transfer path is monitored, and the wireless terminal indicated by the source address of the packet and the wireless base station indicated by the transmitting station address are associated with each other in a table. When a packet is registered and a packet is received, a transfer destination is selected by referring to a table, and the packet is transferred without passing through a redundant transfer path because the tree-shaped transfer path is shortcut-transmitted. Thus, an effect of preventing an increase in transfer delay time and a decrease in throughput can be obtained.

When a packet transmitted from another radio base station by shortcut of a tree-shaped transfer path is transferred, the packet is located in the same direction as the root station (upper direction of the tree-shaped transfer path) from the own station. Since the wireless base station is not selected as the transfer destination, the transfer packet can be prevented from looping, and the same packet can be received a plurality of times and the throughput can be prevented from lowering. In addition, shortcut transmission can be performed without the wireless terminal performing broadcast transmission of the search frame or the all-routes search frame, and the effect of preventing a decrease in throughput and an increase in control load on the wireless terminal can be obtained.

Also, the first number of radio base stations required to relay a packet from the radio base station indicated by the packet transmission station address to the own station, and the radio base station registered in the table in association with the transmission source radio terminal. Since the table is updated by comparing the number of second radio base stations required for relaying a packet from the station to the own station, the amount of redundancy reduction of the transfer path by the shortcut transmission can be further increased, The effect is obtained that the increase in the transfer delay time and the decrease in the throughput can be more effectively prevented.

In each of the radio base stations, the radio base station indicated by the transmitting station address of the packet updates the table according to the position on the tree-shaped transfer path. The advantage that it is possible to prevent the wireless base station from continuing to transmit the shortcut based on the information of the above.

After a wireless terminal is registered in the table or after a wireless terminal being registered in the table is updated, when a predetermined period has elapsed, the registration of the wireless terminal registered in the table is deleted. When the wireless terminal ends the communication, it becomes possible to delete the registration of the table after a predetermined period elapses, and unnecessary after the wireless terminal moves from the wireless base station. Information can be deleted. Therefore, the effect that the amount of memory required for the table can be suppressed is obtained.

A connection notification packet indicating the transfer order of the wireless base station and a connection notification response packet indicating the position of the own station are defined, and the position of the source wireless base station on the tree-shaped transfer path is determined from the connection notification packet. It grasps and inputs the address of its own station to the connection notification response packet and transfers it to the adjacent wireless base station, so that other wireless base stations do not transmit a route search frame, thereby preventing a decrease in throughput. Is obtained.

Further, a connection addition packet indicating the address of the newly connected radio base station and a route notification packet indicating the mutual positional relationship between the radio base stations on the tree-shaped transfer path are defined. Since the wireless base station connected to the transfer path transmits a connection addition packet, and the wireless base station that has received the connection addition packet transmits a route notification packet to the wireless base station that has transmitted the connection addition packet, The transmission of the connection notification response packet of the wireless base station does not need to be performed, and the effect that the consumption of the wireless resources can be further suppressed and the decrease in the throughput can be more effectively prevented can be obtained. The effect that the time until the positional relationship on the transfer path is ascertained can be further reduced can be obtained.

Also, a disconnection notification packet is defined, and when the disconnection of the communication path with the adjacent radio base station is detected, the address of the adjacent radio base station is input to the disconnection notification packet,
Since transmission is performed to all the radio base stations, each radio base station can recognize the radio base station disconnected from the tree-shaped transfer path, and stop the shortcut transmission to this radio base station. Is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio base station according to an embodiment of the present invention.

FIG. 2 is a diagram showing a format of a packet according to the embodiment of the present invention;

FIG. 3 is a flowchart for explaining basic operations 1 to 4 of the radio base station according to the embodiment of the present invention.

FIG. 4 is a flowchart for explaining basic operations 5 and 6 of the radio base station according to the embodiment of the present invention.

FIG. 5 is a flowchart for explaining basic operations 7 to 11 of the radio base station according to the embodiment of the present invention.

FIG. 6 is a flowchart for explaining a basic operation 12 of the radio base station according to the embodiment of the present invention.

FIG. 7 is a diagram for explaining an example of arrangement of wireless base stations according to the embodiment of the present invention.

FIG. 8 is a diagram showing an example of a wireless packet communication network (tree-like transfer path) configured by wireless base stations according to the embodiment of the present invention.

FIG. 9 is a diagram for explaining a first example of packet transmission by the radio base station according to the embodiment of the present invention;

FIG. 10 is a diagram for explaining an example of a shortcut table created in packet transmission example 1 according to the embodiment of the present invention;

FIG. 11 is a diagram for explaining packet transmission example 2 according to the embodiment of the present invention;

FIG. 12 is a diagram illustrating an example of a shortcut table created in packet transmission example 2 according to the embodiment of the present invention;

FIG. 13 is a diagram for explaining a packet transmission example 3 according to the embodiment of the present invention.

FIG. 14 is a diagram illustrating an example of a shortcut table created in packet transmission example 3 according to the embodiment of the present invention.

FIG. 15 is a diagram for explaining an example of packet transmission (when shortcut transmission is not performed) according to the embodiment of the present invention;

FIG. 16 is a diagram for explaining an example of packet transmission (when a wireless terminal moves) according to the embodiment of the present invention;

FIG. 17 is a diagram for explaining an example of a shortcut table created in a packet transmission example (when a wireless terminal moves) according to the embodiment of the present invention;

FIG. 18 is a diagram for explaining an example of packet transmission (in the case of broadcast transmission) according to the embodiment of the present invention;

[Explanation of symbols]

AP, AP1 to AP7 ... Wireless base station, STA, STA
1, STA3 to STA7 ... wireless terminal, 1 ... packet monitor unit, 2 ... shortcut table, 3 ... packet transfer unit, S01 to S14, S20 to S24, S30 to S4
2, S50, S51 ... Step.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiko Inoue 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Masahiro Morikura 3-19 Nishi Shinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation

Claims (14)

[Claims] 1. A wireless packet transfer method in a wireless packet communication network including a plurality of wireless base stations forming a tree-shaped transfer path using a specific wireless base station as a root station and wireless terminals belonging to each wireless base station. In each of the wireless base stations, a packet transferred in a direction approaching the local station on the tree-shaped transfer path is monitored, and a wireless terminal indicated by a source address of the packet and a wireless terminal indicated by a transmitting station address are monitored. Registered in the table in association with the base station, and received a packet from the wireless base station on the tree-shaped transfer path located in the opposite direction to the root station as viewed from the wireless terminal belonging to the own station or the own station The wireless base station associated with the destination wireless terminal on condition that the destination wireless terminal indicated by the destination address of the packet is registered in the table. Is selected as a transfer destination, a packet is transmitted to the wireless base station selected as the transfer destination by shortcutting the tree-shaped transfer path, and transmitted by shortcutting the tree-shaped transfer path from another wireless base station. A wireless base station on the tree-shaped transfer path, which is located in the same direction as the root station when viewed from its own station, is not selected as a transfer destination. 2. Each of the radio base stations monitors a packet transferred from another radio base station by shortcut of the tree-shaped transfer path, and checks a radio terminal and a transmission station address indicated by a source address of the packet. 2. The wireless packet transfer method according to claim 1, wherein the wireless packet transfer method registers the wireless base station indicated by the wireless base station in the table. 3. In each of said radio base stations, when monitoring a packet transferred from another radio base station on said tree-shaped transfer path in a direction approaching its own station, or when said other radio base station transmits said tree-shaped transfer In the case of monitoring a packet transferred by short-cutting a route, and when the source wireless terminal of the packet is registered in the table, the monitored wireless base station indicated by the transmission station address of the packet The first number of wireless base stations required to relay a packet to the own station according to the tree-shaped transfer path, and the tree-shaped transfer path from the wireless base station registered in the table in association with the source wireless terminal And comparing the number of second radio base stations required for relaying a packet to the own station according to the above, that the number of first radio base stations is equal to or greater than the number of second radio base stations. 3. The wireless packet transfer method according to claim 1, wherein the table is registered and updated by associating a wireless base station indicated by a transmission station address of the packet with the source wireless terminal. . 4. In each of the radio base stations, when monitoring a packet transferred from another radio base station on the tree-shaped transfer path in a direction approaching the self-station, or when the tree-shaped transfer is performed from another radio base station. When monitoring a packet transferred by short-cutting a route, and when the transmission source wireless terminal of the packet is registered in the table, the monitored radio base station indicated by the transmission station address of the packet is: The wireless base station indicated by the transmitting station address is not located between the wireless base station registered in the table and the own station in the table in association with the transmitting wireless terminal on the tree-shaped transfer path, The monitoring of the transmitting station address of the packet is performed on the condition that it matches the wireless base station registered in the table in association with the transmitting wireless terminal. Wireless packet transfer method according to any of claims 1 or 2 to the radio base station in association with the said sender wireless terminal and registers updated in the table. 5. A wireless packet transfer method in a wireless packet communication network including a plurality of wireless base stations forming a tree-shaped transfer path using a specific wireless base station as a root station and wireless terminals belonging to each wireless base station. In each of the radio base stations, a packet transmitted by a radio terminal belonging to another radio base station is monitored, and a radio terminal indicated by a source address of the packet and a radio base station indicated by a reception station address are determined. When the packet is received from the wireless terminal belonging to the own station or the wireless base station on the tree-shaped transfer path located in the opposite direction to the root station when viewed from the own station, the packet is registered. Destination wireless terminal indicated by the destination address of the wireless base station associated with the destination wireless terminal on condition that it is registered in the table as a transfer destination Select, shortcut the tree-shaped transfer path, transmit a packet to the wireless base station selected as the transfer destination, and receive a packet transmitted from another wireless base station, shortcut the tree-shaped transfer path In this case, a wireless base station on the tree-shaped transfer path located in the same direction as the root station as viewed from the own station is not selected as a transfer destination. 6. A packet wireless transfer method in a wireless packet communication network including a plurality of wireless base stations forming a tree-shaped transfer path using a specific wireless base station as a root station and wireless terminals belonging to each wireless base station. In each of the radio base stations, a packet transmitted from another radio base station to the radio terminal is monitored, and the radio terminal indicated by the destination address of the packet is associated with the radio base station indicated by the transmission station address in a table. When a packet is received from a wireless terminal belonging to the own station or a wireless base station on the tree-shaped transfer path located in the opposite direction to the root station as viewed from the own station, the destination address of the packet is used. Selecting a wireless base station associated with the destination wireless terminal as a transfer destination on the condition that the indicated destination wireless terminal is registered in the table, When a packet is transmitted to the wireless base station selected as the transfer destination by shortcutting the tree-shaped transfer path, and a packet transmitted by shortcutting the tree-shaped transfer path from another wireless base station is received, A wireless packet transfer method, wherein a wireless base station on the tree-shaped transfer path located in the same direction as the root station as viewed from the own station is not selected as a transfer destination. 7. In each of the radio base stations, a connection notification packet and a connection notification response packet are defined, and the connection notification packet and the connection notification response packet have a path information field in a data part thereof, and the path information field Indicates the transfer order of all the wireless base stations that have transferred the packet, and in the wireless base station newly connected to the tree-shaped transfer path, the connection notification packet is sent to the adjacent wireless base station on the tree-shaped transfer path. The adjacent wireless base station that has transmitted and received the connection notification packet grasps the position of the source wireless base station on the tree-shaped transfer path of the source wireless base station of the connection notification packet from the path information field, and transfers the tree-shaped transfer. Update the route and input the source address of the connection notification packet as the destination address of the connection notification response packet The connection notification response packet is transmitted, and the address of the own station is additionally input to the path information field of the connection notification packet, and the address is transmitted on the tree-shaped transfer path excluding the wireless base station indicated by the transmission station address of the connection notification packet. In the wireless base station that has transferred to all the adjacent wireless base stations and has received the connection notification response packet, the position on the tree-shaped transfer path of the transmission source wireless base station of the connection notification response packet is determined from the path information field. Recognize and update the tree-shaped transfer route. If the destination address of the connection notification response packet does not match the address of the own station, add the address of the own station to the route information field of the connection notification response packet and transfer. The wireless packet transfer method according to any one of claims 1 to 6, wherein: 8. In each of the radio base stations, a connection addition packet and a route notification packet are defined in a packet transferred between the radio base stations, and the connection addition packet includes a connection radio base station field in a data portion thereof. Has, the connection radio base station field indicates the address of the radio base station newly connected to the source radio base station of the connection addition packet, the path notification packet has a path information table field in its data part, The route information table field indicates the mutual positional relationship between the wireless base stations on the tree-shaped transfer path known by the source wireless base station of the packet, and indicates the wireless base station newly connected to the tree-shaped transfer path. The station transmits the connection addition packet to the wireless base station connected to the communication path, and transmits the wireless base At the radio base station that has received the connection addition packet whose source is the base station, transmits the route notification packet to the transmission source radio base station of the connection addition packet, and transmits the connection addition packet to the connection notification packet. A wireless base station that transfers the connection addition packet to a wireless base station other than the wireless base station indicated by the station address to an adjacent wireless base station on the tree-shaped transfer path and that has a source other than the wireless base station adjacent to the tree-shaped transfer path The station updates the tree-shaped transfer path by grasping that the transmission source radio base station of the connection notification packet has connected the communication path with the radio base station indicated by the connection radio base station field of the connection addition packet, The connection addition packet is sent to all wireless base stations adjacent on the tree-shaped transfer path except the wireless base station indicated by the transmission station address of the connection addition packet In the wireless base station that has received the route notification packet,
7. The wireless communication apparatus according to claim 1, wherein a position of another wireless base station on a tree-shaped transfer path is grasped from the path information table field to update the tree-shaped transfer path. Packet transfer method. 9. In each of the radio base stations, a disconnection notification packet is defined in a packet transferred between the radio base stations, and the disconnection notification packet has a disconnection radio base station field in a data part. Each wireless base station has a function of detecting disconnection of a communication path with an adjacent wireless base station on a tree-shaped transfer path, and when detecting disconnection of a communication path with the adjacent wireless base station, In the wireless base station that has received the disconnection notification packet, inputs the address of the wireless base station to be transmitted to the disconnected wireless base station field, transmits the disconnection notification packet to all the wireless base stations on the tree-shaped transfer path, ,
The method according to claim 1, further comprising recognizing that a communication path between the wireless base station indicated by the disconnected wireless base station field and the wireless base station that has transmitted the disconnection notification packet has been disconnected, and updating a tree-shaped transfer path. Item 9. The wireless packet transfer method according to any one of Items 7 and 8. 10. The wireless packet according to claim 1, wherein each of the wireless base stations does not transmit a packet transmitted by broadcast by shortcutting a tree-shaped transfer path. Transfer method. 11. In each of the wireless base stations, after a wireless terminal is registered in the table or after a wireless terminal being registered in the table is updated, a wireless terminal is registered in the table when a predetermined period elapses. 10. The wireless packet transfer method according to claim 1, wherein the registration of the wireless terminal is deleted. 12. A radio base station in a radio packet communication network in which a tree-shaped transfer path is configured with a specific radio base station as a root station, wherein a radio terminal indicated by a packet source address and a radio station indicated by a transmission station address A table for registering the base station in association with the base station, a packet transferred in a direction approaching the own station on the tree-shaped transfer path, and a wireless terminal and a transmitting station indicated by a source address of the packet. A monitoring unit that registers the wireless base station indicated by the address in the table in association with the table, and a transfer unit that forwards a packet from a wireless terminal belonging to the own station or another wireless base station with reference to the table. Wherein the transfer unit is configured to receive a packet from a wireless terminal belonging to the own station or a wireless base station on the tree-shaped transfer path located in a direction opposite to the root station when viewed from the own station. If the destination wireless terminal indicated by the destination address of the packet is registered in the table, the wireless base station associated with the destination wireless terminal is selected as the transfer destination, and the transfer is performed. If a packet is transmitted to the selected wireless base station by shortcut of the tree-shaped transfer path, and a packet transmitted from another wireless base station by shortcut of the tree-shaped transfer path is received, A radio base station which does not select a radio base station on the tree-shaped transfer path located in the same direction as the root station as viewed from a station as a transfer destination. 13. A radio base station in a radio packet communication network in which a tree-shaped transfer route is configured with a specific radio base station as a root station, wherein a radio terminal indicated by a packet source address and a radio terminal indicated by a reception station address A table for registering a base station in association with the base station, and monitoring a packet transmitted by a wireless terminal belonging to another wireless base station, and checking a wireless terminal indicated by a source address of the packet and a radio indicated by a receiving station address. A monitoring unit for registering the base station in association with the base station, and a transfer unit for transferring a packet from a wireless terminal belonging to the own station or another wireless base station with reference to the table; The unit has received a packet from a wireless terminal belonging to the own station or a wireless base station on the tree-shaped transfer path located in a direction opposite to the root station as viewed from the own station. If the destination wireless terminal indicated by the destination address of the packet is registered in the table, the wireless base station associated with the destination wireless terminal is selected as a transfer destination, and the tree-shaped transfer path is selected. When a packet is transmitted to the radio base station selected as the transfer destination by shortcut, and a packet transmitted by shortcut of the tree-shaped transfer path from another radio base station is received, the route is viewed from the own station. A wireless base station which does not select a wireless base station on the tree-shaped transfer path located in the same direction as a station as a transfer destination. 14. A radio base station in a radio packet communication network that configures a tree-shaped transfer path with a specific radio base station as a root station, wherein the radio terminal indicated by the packet destination address and the radio base indicated by the transmission station address Monitors a table for registering stations in association with each other, monitors a packet transmitted from another wireless base station to a wireless terminal, and associates the wireless terminal indicated by the destination address of the packet with the wireless base station indicated by the transmitting station address And a transfer unit that transfers a packet from a wireless terminal belonging to the own station or another wireless base station with reference to the table, and the transfer unit refers to the table. When a packet is received from a wireless terminal on the tree or a wireless base station on the tree-shaped transfer path located in a direction opposite to the root station as viewed from the own station, The wireless base station associated with the destination wireless terminal is selected as a transfer destination on condition that the destination wireless terminal indicated by the destination address of the packet is registered in the table, and the tree-shaped transfer path is shortcut. Transmitting a packet to the wireless base station selected as the transfer destination, and receiving a packet transmitted from another wireless base station by shortcut of the tree-shaped transfer path, the local station and the root station A wireless base station which does not select a wireless base station on the tree-shaped transfer path located in the same direction as a transfer destination.