JP2007201782A - Wireless packet communication system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manage the number of multihops from each mobile terminal to a GW-AP with fewer pieces of information by using a simple message exchange method in a multihop network wherein priority control is carried out on the basis of the number of hops of the mobile terminals from the GW-AP. <P>SOLUTION: Upon the receipt of a terminal registration request from an access point 12b, an access point 12a registers an identifier of a mobile terminal 13b and the count of the number of hop counter in the terminal registration request and an identifier of the access point 12b to a registration terminal management list stored in the access point 12a itself, increments the count of the number of hops counter by one and transfers the resulting terminal registration request. A GW-AP 11 registers an identifier of the mobile terminal 13b and the count of the number of hops counter in the terminal registration request and the identifier of the access point 12a to a registration terminal management list stored in the GW-AP 11 itself. The access point 12a and the GW-AP 11 are respectively provided with a plurality of queues corresponding to the number of hops, and earlier transmit traffic addressed to a mobile terminal with many number of hops. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless packet communication system and a wireless packet communication method for preferentially transmitting a specific wireless packet in a wireless communication system that transfers wireless packets between a plurality of access points.

  The wireless packet communication is a communication form adopted in various systems including a wireless LAN (Local Area Network). The wireless LAN standard is being standardized by the IEEE 802.11 committee and established as the IEEE 802.11 standard (see Non-Patent Document 1, especially Chapter 9). In this standard, two communication modes are defined. One is an infrastructure mode, which is a communication mode used in a wireless network formed by connecting a wireless terminal called a mobile terminal to a wireless terminal called an access point through a wireless medium. The access point is basically connected to a wired network such as Ethernet (registered trademark), and has a bridge function between the wireless network and the wired network. That is, when viewed from the mobile terminal, the access point serves as an entrance to the wired network. The other is an ad hoc mode, which is a communication mode used in a closed network composed only of mobile terminals.

FIG. 9 shows a configuration example of a wireless packet communication apparatus of the IEEE 802.11 system. In the figure, the wireless packet communication device includes a transmission / reception processing unit, a transmission buffer, a wireless packet generation unit, a transmission control unit, and a header removal unit. The transmission / reception processing unit includes a modulation unit, a radio transmission unit, an antenna, a radio reception unit, a demodulation unit, a packet selection unit, and a carrier detection unit.
In the IEEE 802.11 system, each wireless station detects whether a signal is output (carrier sense) in a frequency band (channel) used by the local station prior to transmission of the wireless packet, and no signal is output. In this case, the wireless packet transmission process is started, and if it is output, the transmission process is postponed.

The wireless signal received via the antenna is input to the wireless reception unit. The radio reception unit performs reception processing including frequency conversion, filtering, quadrature detection, and AD conversion on the input radio signal. When the antenna connected to the wireless receiver is not used for transmission, the wireless signal on the wireless propagation path in the channel is always input, and the RSSI (Received Signal Strength Indicator) indicating the received power strength of the wireless signal. ) Signal is output to the carrier detector. When a radio signal is received, a baseband signal that has been subjected to reception processing by the radio reception unit is output to the demodulation unit.
The carrier detection unit determines the channel state using the RSSI signal input from the radio reception unit. If the received power intensity is below a predetermined threshold value for a certain period, it is determined that the channel is idle, and otherwise, the channel is determined to be busy. This determination result is output as a carrier sense result to the transmission control unit.

On the other hand, a data frame is input to the transmission buffer from an upper layer of a device (PC (Personal computer) or the like) to which a wired network or a wireless terminal is connected. When a data frame is input, the transmission buffer notifies the transmission control unit that the data frame has been input. Alternatively, the transmission buffer sequentially outputs information on the accumulated data frames (number of data frames, data size, data frame destination address, etc.) to the transmission control unit.
The transmission control unit determines whether to start the transmission process based on the accumulated information of the data frame input from the transmission buffer and the carrier sense result input from the carrier detection unit.
When data frames are accumulated in the transmission buffer and the channel is empty, it is determined that transmission processing is started. In other cases, the transmission process is not started. When the transmission control unit determines that transmission processing is started, the transmission control unit instructs the transmission buffer to output a data frame. When the transmission buffer is instructed to output the data frame by the transmission control unit, the transmission buffer outputs the data frame accumulated at the head of the buffer to the wireless packet generation unit.
The wireless packet generator generates a wireless packet by adding a header and an error detection code including control information such as a destination wireless station address and a local station address to the data frame input from the transmission buffer. The generated radio packet is modulated by the modulation unit, subjected to transmission processing including DA conversion, frequency conversion, filtering, and power amplification by the radio transmission unit, and transmitted as a radio signal from the antenna.

As described above, a radio signal is converted into a baseband signal via an antenna and a radio reception unit and input to the demodulation unit. The baseband signal is demodulated by the demodulator and then input to the packet selector as a received packet.
The packet selection unit analyzes the control information included in the header of the received packet and outputs the received packet to an appropriate processing unit. When the destination wireless station address matches the own station address, the received packet is output to the header removing unit, and when it does not match, the received packet is discarded. In addition, although detailed explanation is omitted here, the packet selection unit, when receiving a management packet in which authentication information or the like is described or a control packet in which delivery confirmation information or the like is described, is based on the information. They are output to a management packet processing unit that performs authentication processing and the like, and a control packet processing unit that performs delivery confirmation processing and the like.
The header removing unit removes the header of the received packet, extracts the data frame, and outputs the data frame to the upper layer of the wired network or connected device as the received data frame.
When such a wireless packet communication device is used, each wireless terminal can independently perform channel access control by carrier sense and transmit a wireless packet.

  By the way, the IEEE802.11 standard allows communication between access points. A system that performs communication between access points is called WDS (Wireless Distribution System), and wireless packets are transferred between access points. For example, there is a system that bridges a plurality of wired networks via an access point.

  In general, in order to construct a wide-area wireless network, it is necessary to install a plurality of access points and connect each access point with a wire. On the other hand, as an effective usage method of WDS, a method of transferring a wireless packet by connecting a plurality of access points via a wireless medium is conceivable. If this method is used, a plurality of installed access points can be wirelessly connected, so there is no need to lay a wired network, and there is an advantage that a wireless network can be easily constructed. An access point that is connected to a wired network and serves as a gateway to an intranet or the Internet is called a gateway access point (hereinafter referred to as “GW-AP”), and multiple access points are used to transfer wireless packets to this GW-AP. A packet transfer method that performs wireless transfer via a point is called multi-hop transfer.

On the other hand, in the IEEE802.11 standard, priority control is introduced in order to transmit real-time traffic such as voice and video with high quality (see Non-Patent Document 2, especially Chapter 9). In this priority control, traffic input to the access point is divided into categories such as voice, video, and non-real time traffic, and stored in a queue corresponding to them. Each queue is assigned a priority, and transmission control is performed so that audio and video are transmitted more frequently.
IEEE 802.11, “Wireless LAN Medium Access Control (MAC) and Physical (PHY) Layer Specifications”, August 1999 IEEE 802.11, “Medium Access Control (MAC) Quality of Service Enhancements”, January 2005

  In general, when performing multi-hop transfer, as the number of times wireless transfer is performed (hereinafter, the number of multi-hops or the number of hops) increases, the time required to transfer a packet (packet transfer time) becomes longer. For example, when transferring traffic with high real-time properties such as voice, there is a problem that the quality deteriorates as the packet transfer time becomes longer. In order to solve this, it is conceivable to preferentially transfer a packet having a large number of hops. However, in the frame format defined in the current IEEE 802.11 standard, each access point does not have a field for notifying the number of multihops from the GW-AP, so priority control based on the number of hops is performed. I can't do it. Also, changing the standard frame format is not desirable in terms of compatibility with existing products.

  On the other hand, methods such as AODV (Ad hoc On Demand Distance Vector) and OLSR (Optimized Link State Routing) have been proposed as protocols for routing at layer 3. In particular, AODV specifies that each node manages the number of hops between the nodes, and by using this in layer 2, priority control based on the number of hops can be performed. However, in AODV, when a routing table for route selection is created, a control packet is notified to all nodes in the network, so that there is a problem that traffic in the network temporarily increases significantly. The reason why the control packet is broadcast to the entire network in this way is because AODV considers that the mobility of the node is supported, but in a multi-hop network configured by WDS, the node is an access point. Because it is generally fixed, there is no need to consider mobility. That is, since a route for transferring a packet is basically determined, a method for transferring a control packet more efficiently is desirable. Furthermore, in order to use AODV, it is necessary that all nodes constituting the network support AODV.

  The present invention has been made in view of such circumstances, and in a multi-hop network that performs priority control based on the number of hops from a GW-AP of a mobile terminal, each mobile An object of the present invention is to provide a radio packet communication system and a radio packet communication method capable of managing the number of multihops from a terminal to a GW-AP.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a wireless packet communication system that transmits and receives wireless packets between a plurality of base stations. Each of the base stations indicates that a mobile terminal belongs to the mobile station. When it recognizes, sets the identifier of the mobile terminal and the information of the hop number counter used to measure the number of hops, which is the number of the base stations that perform relay processing between the mobile terminal and the own station The base station serving as a relay station from the base station to which the mobile terminal belongs to the gateway access point that is the base station connected to the wired network, Storage means for storing a registered terminal management list including information on the number of hops for each mobile terminal that accesses the wired network via the network, and the other base station When receiving the terminal registration request message, the mobile terminal identifier and hop number counter information set in the terminal registration request message, and the other base station that directly transferred the terminal registration request message to the own station The list management means for writing to the registered terminal management list in the storage means included in the local station, and the hop number counter included in the terminal registration request message received by the list management means of the local station Transfer means that increments the value by 1 and transfers the priority control of radio packets destined for each mobile terminal to the number of hops of the mobile terminal indicated by the registered terminal management list in the storage means provided in the local station Based on priority control means, and the gateway access point accesses the wired network via its own station. Storage means for storing a registered terminal management list including information on the number of hops for each mobile terminal to be registered, and when the terminal registration request message is received from another base station, the terminal registration request message is set. A registration terminal in the storage means provided in the local station by associating the identifier of the mobile terminal and the information of the hop number counter with the information of the identifier of the other base station that directly transferred the terminal registration request message to the local station. List management means for writing in the management list and priority control of radio packets destined for each mobile terminal are performed based on the number of hops of the mobile terminal indicated by the registered terminal management list in the storage means provided in the local station. A wireless packet communication system comprising: priority control means.

  According to a second aspect of the present invention, in the wireless packet communication system according to the first aspect, the transmission means of each base station recognizes that the mobile terminal belonging to the own station has disconnected the connection. The base station list management means that serves as a relay station transmits a terminal deletion request message in which the identifier of the mobile terminal is set, and when receiving the terminal deletion request message from another base station, The information corresponding to the identifier of the mobile terminal set in the terminal deletion request message is deleted from the registered terminal management list in the storage means, and the transfer means of the base station serving as a relay station is provided in the own station The terminal deletion request message received by the list management means is transferred, and the list management means of the gateway access point receives the terminal deletion request message from another base station. When receiving, from the registration terminal management list in the storage means included in the own station, and deletes the information corresponding to the identifier of the mobile terminal that is set to the terminal deletion request message, characterized in that.

  According to a third aspect of the present invention, in the wireless packet communication system according to the second aspect of the present invention, there is provided a database for storing parameters relating to operation of the own station, including at least information on identifiers of mobile terminals belonging to the own station. The base station transmission means periodically accesses the database, recognizes the increase / decrease in the number of mobile terminals belonging to the mobile station by comparing parameters with the previous access, and the mobile terminal Create and send a terminal registration request message for the mobile terminal when the mobile terminal is increasing, and create and send a terminal deletion request message for the mobile terminal when the mobile terminal is low And

  According to a fourth aspect of the present invention, in the wireless packet communication system according to the second aspect, the terminal registration request message is triggered by the fact that the transmitting means of the base station recognizes that the connection processing with the mobile terminal has been completed. Is created and transmitted, and a terminal deletion request message is created and transmitted triggered by the completion of the disconnection process with the mobile terminal.

  In order to solve the above problem, the invention according to claim 5 is a wireless packet communication method used in a wireless packet communication system for transmitting and receiving wireless packets between a plurality of base stations. The base station that is a relay station from the station to the gateway access point that is the base station connected to the wired network, and each mobile terminal that accesses the wired network via its own station For the mobile terminal and the own station, and having a storage means for storing a registration terminal management list including information on the number of hops that is the number of the base stations that perform the relay processing, each base station, Used to measure the identifier of the mobile terminal and the number of hops to the mobile station when the mobile terminal recognizes that it belongs to the mobile station. A terminal registration request message in which information on the hop number counter is set is transmitted, and the base station serving as a relay station receives the terminal registration request message from another base station, and the movement set in the terminal registration request message The registered terminal management list in the storage means provided in the own station by associating the information of the terminal identifier and the hop number counter with the information of the identifier of the other base station that directly transferred the terminal registration request message to the own station And the hop number counter value included in the received terminal registration request message is incremented by 1 and transferred, and the gateway access point receives the terminal registration request message from another base station, and receives the terminal registration request message. The mobile terminal identifier and hop counter information and the corresponding terminal registration request message to the local station While associating with the identifier information of the other base station that has been contact-transferred and writing it in the registered terminal management list in the storage means provided in the own station, the base station that is to be the gateway access point and relay station, A wireless packet communication method characterized in that priority control of a wireless packet destined for a mobile terminal is performed based on the number of hops of the mobile terminal indicated by a registered terminal management list in the storage means provided in the local station. is there.

  According to a sixth aspect of the present invention, in the wireless packet communication method according to the fifth aspect, when each of the base stations recognizes that the mobile terminal belonging to the own station has disconnected, the mobile station A terminal deletion request message in which an identifier of the terminal is set is transmitted, and the base station serving as a relay station receives the terminal deletion request message from another base station, and manages registered terminals in the storage means provided in the own station. Delete the information corresponding to the identifier of the mobile terminal set in the terminal deletion request message from the list, transfer the received terminal deletion request message, and the gateway access point deletes the terminal from the other base station The identifier of the mobile terminal set in the terminal deletion request message from the registered terminal management list in the storage means that is received by the request station It deletes the corresponding information, characterized in that.

  The invention according to claim 7 is the radio packet communication method according to claim 6, wherein the base station includes at least information on an identifier of a mobile terminal belonging to the own station, and is a parameter relating to operation of the own station. The number of mobile terminals increases by recognizing increase / decrease in the number of mobile terminals belonging to the own station by periodically accessing the database and comparing parameters with the previous access. A terminal registration request message for the mobile terminal is created and transmitted, and if the number of mobile terminals is reduced, a terminal deletion request message for the mobile terminal is created and transmitted. To do.

  The invention according to claim 8 is the wireless packet communication method according to claim 6, wherein the transmission means of the base station recognizes that the connection processing with the mobile terminal has been completed, and triggers a terminal registration request message. Is created and transmitted, and a terminal deletion request message is created and transmitted triggered by the completion of the disconnection process with the mobile terminal.

  According to the present invention, in each access point (base station) serving as a relay station and GW-AP, a registered terminal management list in which only the identifier of each mobile terminal, the access point to be transferred next, and the number of hops is described. By creating / managing, it is possible to manage the multi-hop numbers of all mobile terminals accessing the wired network via the access point and GW-AP. In order to create this registered terminal management list, when the access point that the mobile terminal requests to connect recognizes the connection of the mobile terminal, the access point directly transmits the wireless packet when transmitting the wireless packet to the GW-AP. Since a message for requesting registration of a terminal is transmitted only to an access point that is a transmission destination, an excessive increase in traffic on the network is suppressed. In addition, since a normal data frame is used as means for notifying each access point and GW-AP of the number of hops of each mobile terminal, the same procedure as in conventional multi-hop forwarding can be used. It is not necessary to modify the transport protocol of the network, and it is not necessary to have all the nodes implement the layer 3 routing protocol.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a wireless communication system assumed in the present invention. A GW-AP (gateway access point) 11 is connected to a wired network 10 such as Ethernet (registered trademark), and each mobile terminal accesses the wired network 10 via the GW-AP 11. Here, the GW-AP 11 is connected to a bridge device. The access point 12a (access point A) is wirelessly connected to the GW-AP 11, and the access point 12b (access point B) is wirelessly connected to the access point 12a. That is, the mobile terminal 13b (mobile terminal B) connected to the access point 12b accesses the wired network 10 via the access point 12b, the access point 12a, and the GW-AP 11. The GW-AP 11 and the access points 12a and 12b have the same configuration as that of the conventional wireless packet communication apparatus shown in FIG.
In the following, any access point such as the access points 12a and 12b is referred to as an access point 12, and any mobile terminal such as the mobile terminal 13a (mobile terminal A) and 13b is referred to as the mobile terminal 13. It describes.

  FIG. 2 shows a flow of messages exchanged between the nodes of this embodiment. When the mobile terminal 13b receives the beacon signal notified from the access point 12b and recognizes that it is a connectable access point, the mobile terminal 13b transmits an authentication request message to the access point 12b (step S101). Upon receiving the authentication request message, the access point 12b performs an authentication process on the mobile terminal 13b that has transmitted the authentication request message, and transmits an authentication response message (step S102). If the authentication is successful, the mobile terminal 13b transmits a connection request message (step S103), and the access point 12b returns a connection response message (step S104). With the above procedure, the belonging process of the mobile terminal 13b to the access point 12b is completed. Up to here, it is the same as the conventional wireless communication system. When recognizing that the mobile terminal 13b belongs, the access point 12b transmits a terminal registration request message of the mobile terminal 13b to the GW-AP 11 (step S105). A method for recognizing that the mobile terminal 13b belongs and a method for creating a terminal registration request message will be described later.

  The terminal registration request message includes a mobile terminal identifier (for example, a MAC (Media Access Control) address) and a counter that counts the number of hops that are the number of nodes that perform relay processing between the mobile terminal and the local station ( Hop number counter) is included as an information element. Here, since the access point 12b is not directly connected to the GW-AP 11, the access point 12a relays the terminal registration request message. Therefore, the access point 12b transmits a terminal registration request message to the access point 12a using a WDS (Wireless Distribution System) frame. As shown in FIG. 3, the WDS frame differs in the number and definition of address fields from a radio packet that transmits normal data. In FIG. 3, a normal data frame is composed of frame control, duration, MAC header consisting of address 1, address 2 and address 3, sequence control, data, and error detection code field. It consists of fields of frame control, duration, address 1, address 2, address 3, address 4 and sequence control, MAC header, data, and error detection code.

  In FIG. 2, each access point 12 has a registered terminal management list for managing all mobile terminals 13 that access the wired network 10 via its own station, and the access point 12a receives a terminal registration request. When the message is received, the identifier of the mobile terminal and the value of the hop number counter are extracted, and the identifier (for example, the MAC address) of the access point (in this case, the access point 12b) directly transferring the terminal registration request message is transferred to the transfer destination. It is acquired as a point identifier and registered in the registered terminal management list (step S106). Since the MAC address of the access point is included in the header of the MAC frame, it can be easily obtained. Next, the access point 12a increments the value of the hop number counter by one, and similarly transfers the terminal registration request message to the GW-AP 11 using the WDS frame (step S107).

Like other access points, the GW-AP 11 has a registered terminal management list. Upon receiving a terminal registration request message, the GW-AP 11 extracts the identifier of the mobile terminal and the value of the hop number counter, and the terminal registration request message Is obtained as the identifier of the transfer destination access point, and the registered terminal management list is updated (step S108). When the update of the registered terminal management list is completed, a terminal registration response (terminal registration confirmation) message is transmitted to the transfer destination access point (step S109). The terminal registration response message includes an identifier of the mobile terminal and a registration completion status as information elements.
When receiving the registration completion confirmation message, the access point 12a transfers it to the access point 12b (step S110). By receiving the terminal registration response message, the access point 12b recognizes that the mobile terminal 13b has been registered in the GW-AP 11, and ends the process.

  FIG. 4 shows a processing procedure of the access point 12 when the mobile terminal 13 requests the access point 12 for connection processing in the access point 12 of the present embodiment. Here, as shown in FIG. 2, a case where the mobile terminal 13b requests connection processing from the access point 12b will be described.

  When the access point 12b receives the authentication request addressed to itself, the access point 12b performs an authentication process on the mobile terminal 13b that has transmitted the authentication request, and returns the result to the mobile terminal 13b (step S11). Here, in order to perform the authentication process, the mobile terminal 13b encrypts the text received from the access point 12b using a predetermined encryption key, and the access point 12b checks the validity, or the access A method of inquiring to an authentication server that performs authentication processing instead of the point 12b can be considered, but the method of authentication processing is not limited in this embodiment. When the authentication process is completed, the access point 12b performs a connection process. That is, the mobile terminal 13b transmits a connection request, and the access point 12b returns a connection response (step S12). In the connection process, the transmission speed that can be used between the access point and the mobile end, the availability of power save mode, and the like are checked.

  When the connection process of the mobile terminal 13b is completed, the access point 12b creates and transmits a terminal registration request message addressed to the GW-AP 11 and starts a timer (steps S13 and S14). As shown in FIG. 6, the terminal registration request message includes a GW-AP identifier, a transmission source access point identifier, an identifier of a mobile terminal to be registered, a hop number counter, and a registration / deletion status. The access point 12b receives a terminal registration confirmation message corresponding to the terminal registration request message. As shown in FIG. 6, the terminal registration confirmation message includes a transmission source access point identifier, a GW-AP identifier, a mobile terminal identifier, and a registration / deletion confirmation status. By confirming that the registration / deletion confirmation status is “success”, the access point 12b recognizes that the target terminal has been registered in the GW-AP 11, and completes the processing (step S15). When the registration / deletion status is “failure”, retransmission processing is performed as necessary. Further, when the access point 12b does not receive the terminal registration confirmation message from the GW-AP 11 within a predetermined period, that is, when the timer started at the time of transmitting the terminal registration request message in step S14 times out The disconnection process is performed on the mobile terminal 13b (steps S16 and S17).

  FIG. 5 shows a terminal registration request message relay processing procedure in the access point 12 of this embodiment and a terminal registration request message reception processing procedure in the GW-AP 11. For example, in FIG. 2, the access point 12a performs this relay processing procedure. When the access point 12 and the GW-AP 11 receive the terminal registration request message, the access point 12 and the GW-AP 11 extract the identifier and hop number of the mobile terminal, and the access point 12 that last transmitted the terminal registration request message included in the header of the MAC frame. Then, it is extracted as the next transfer destination access point (step S21). These pieces of information are registered in the registered terminal management list managed by the access point 12 that has received the terminal registration request message or the GW-AP 11 itself. FIG. 7 shows an example of a registered terminal management list held by the GW-AP 11.

  Next, the access point 12 and the GW-AP 11 confirm whether or not the received terminal registration request message is a message addressed to the own station (step S22). If the message is addressed to the own station, the process proceeds to step S25; Proceed to S23. If it is not addressed to the own station (step S22: NO), the value of the hop number counter is incremented by 1 (step S23), and the terminal registration request message is transferred (step S24). On the other hand, if it is addressed to the own station (step S22: YES), a terminal registration confirmation message (FIG. 6) is created and transmitted (steps S25 and S26).

  Next, a method for recognizing that the mobile terminal 13 belongs to an access point and a method for creating a terminal registration confirmation message will be described. In the present embodiment, a method of using an MIB (Management Information Base) that is a database of management parameters for managing the access point 12 will be described. The MIB includes parameters used in various controls necessary for the access point 12 to operate normally, information on the mobile terminal 13 connected to the access point 12, and the like.

FIG. 8 shows a procedure for creating a terminal registration confirmation message in the access point 12 of this embodiment. The access point 12 periodically accesses the MIB and confirms the mobile terminal 13 connected to its own station. In order to perform processing periodically, the access point 12 is provided with a timer, and executes the processing whenever the time limit is reached. When the timer expires, the access point 12 accesses the MIB and acquires the identifiers of all the mobile terminals 13 connected to the own station (step S31). These identifiers are compared with the connected terminal management list (only the identifier of the mobile terminal is described), which is a list for managing the mobile terminal 13 connected to the own station by the access point 12, and there is a difference. In this case, the connected terminal management list is updated. If it is confirmed that there is a difference based on the comparison result, the access point 12 creates and transmits a terminal registration (deletion) request (steps S34 and S35). When the number of mobile terminals 13 is increased compared to the list, a terminal registration request message in which identifiers of the increased mobile terminals 13 are set is created. A set terminal deletion request message is created. As shown in FIG. 6, the terminal deletion request message has the same field configuration as the terminal registration request message. When a plurality of differences occur, registration (deletion) can be requested collectively by combining a plurality of information elements of the terminal deletion request message and the terminal registration request message shown in FIG. is there. When a terminal registration (deletion) request is transmitted, a timer is started in preparation for the next confirmation, and the process is terminated. The terminal deletion request message is forwarded to the GW-AP 11 via the access point 12, but the access point 12 that performs the relay does not change the value of the hop number counter in the terminal deletion request message. To the access point 12 or the GW-AP 11. Receiving the terminal deletion request message, the access point 12 and the GW-AP 11 delete information corresponding to the identifier of the mobile terminal included in the received terminal deletion request message from the registered terminal management list held by itself. When the registration deletion processing is completed, the access point 12 and the GW-AP 11 create and transmit a terminal registration deletion confirmation message. As shown in FIG. 6, the terminal registration deletion confirmation message has the same field configuration as the terminal registration confirmation message.
In this way, in the method using MIB, it is possible to perform terminal registration processing based only on MIB information. In general, the MIB can be used also in the application layer, and thus can be realized only by adding an application without modifying an existing apparatus.

  As a method for recognizing that the mobile terminal 13 has belonged to the access point 12, the movement that has belonged to the own station is triggered by the end of the belonging process between the mobile terminal 13 and the access point 12. As a method for recognizing that the terminal 13 has disconnected, a method that uses the completion of the disconnection process between the mobile terminal 13 and the access point 12 as a trigger is also possible. In this case, it is necessary to create and transmit a terminal registration confirmation message and a terminal deletion request message in layer 2. When creating a message using such a method, an Action frame defined by the IEEE 802.11 standard can be used. Note that a message creation method, a relay method, a processing method, and the like are the same as the method using the MIB described above, and are as described above.

  Information on each mobile terminal 13 and its number of hops registered in the GW-AP 11 as described above is used as follows, for example. That is, in the configuration of FIG. 1, the GW-AP 11 has the hop count of the mobile terminal 13a as 1 and the hop count of the mobile terminal 13b as 2 from the information on the hop count registered in the registered terminal management list (FIG. 7). Recognize that. That is, in order to recognize that the mobile terminal 13b is far from the mobile terminal 13a, control is performed to reduce the transfer time by giving high priority to the traffic addressed to the mobile terminal 13b. As this control method, the GW-AP 11 includes two queues, and associates each queue with a hop number 1 and a hop number 2. The traffic input from the wired network 10 to the GW-AP 11 is stored in a queue according to the destination (the number of hops). The GW-AP 11 has an independent carrier sense function for each queue, and the queue (carrier parameter) used for carrier sense processing is differentiated between the queues, so that a queue with a high priority obtains a transmission right. Set to be easy. As a result, traffic destined for a mobile terminal with a large number of hops is transmitted earlier, and the quality of traffic with high real-time characteristics can be improved. At this time, when there is an access point 12 further one hop away, the GW-AP 11 recognizes 3 and the access point 12a recognizes 2 regarding the number of hops of the mobile terminal 13 connected to the access point 12. To do. The GW-AP 11 stores a wireless packet destined for the mobile terminal 13 in a high priority queue and preferentially transmits it. Similarly, the access point 12a also holds a queue corresponding to the number of hops, and radio packets with a large number of hops are stored in a queue with a high priority and transmitted with priority. As described above, since the wireless packets of the mobile terminal 13 located farther from the GW-AP 11 are transmitted one after another, the transfer time is reduced.

  According to the present embodiment, each access point 12 and GW-AP 11 creates / manages a registered terminal management list in which only the identifier of each mobile terminal, the access point to be transferred next, and the number of hops are described. Thus, it is possible to manage the multi-hop number of all mobile terminals 13 that access the wired network 10 via the access point 12 and the GW-AP 11. In order to create this registered terminal management list, when the access point 12 requested by the mobile terminal 13 recognizes the connection of the mobile terminal 13, the access point 12 directly transmits a wireless packet to the GW-AP 11. Since a message requesting registration of a terminal is transmitted only to the access point 12 that is a destination for transmitting a wireless packet, an excessive increase in traffic on the network is suppressed. In addition, as a means for notifying each access point 12 and GW-AP 11 of the number of hops of each mobile terminal 13, a normal data frame is used and the same procedure as in conventional multi-hop transfer is used. It is not necessary to modify the conventional wireless packet transfer protocol, and it is not necessary to have all the nodes implement the layer 3 routing protocol.

  The embodiment of the present invention has been described above. The access point 12 executes the processing shown in FIGS. 4, 5, and 8, and the GW-AP 11 executes the processing shown in FIG. The means for performing the processing may be realized by dedicated hardware (for example, wired logic or the like), and is configured by a memory and a CPU (central processing unit), and executes a program loaded from the memory. The function may be realized by. Further, the computer for reading the program for realizing the means for executing the processing shown in FIGS. 4, 5 and 8 in the access point 12 and the means for executing the processing shown in FIG. 8 in the GW-AP 11. Necessary processing may be performed by recording in a possible recording medium, reading the program recorded in the recording medium into a computer system, and executing the program. The “computer system” here includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It also includes a device (transmission medium or transmission wave) and a device that holds a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or client in that case. The program may be for realizing a part of the functions described above, and further, a program that can realize the functions described above in combination with a program already recorded in a computer system, a so-called difference file (difference). Program).

It is a figure which shows the structural example of the radio | wireless communications system by one embodiment of this invention. It is a figure which shows the flow of the message exchanged between each node of the radio | wireless communications system by the embodiment. It is a figure which shows the structure of the WDS frame used for the radio | wireless communications system by the embodiment. It is a figure which shows the process sequence of the connection request destination access point by the embodiment. It is a figure which shows the process sequence of the relay access point and GW-AP by the embodiment. It is a figure which shows the message used for the access point and GW-AP by the embodiment. It is a figure which shows the registration terminal management list | wrist managed by GW-AP by the embodiment. It is a figure which shows the preparation procedure of the terminal registration confirmation message in the access point by the embodiment. It is a figure which shows the structural example of the conventional radio | wireless packet communication apparatus.

Explanation of symbols

10 ... Wired network 11 ... GW-AP
12a ... Access point (Access point A)
12b ... access point (access point B)
13a ... Mobile terminal (mobile terminal A)
13b ... Mobile terminal (mobile terminal B)

Claims (8)

In a wireless packet communication system that transmits and receives wireless packets between a plurality of base stations,
Each said base station
In order to measure the number of hops, which is the number of base stations that perform relay processing between the mobile terminal and the mobile station when the mobile terminal recognizes that the mobile terminal belongs to the mobile station Comprising a transmission means for transmitting a terminal registration request message in which information of a hop number counter to be used is set,
The base station that serves as a relay station from the base station to which the mobile terminal belongs to the gateway access point that is the base station connected to the wired network,
Storage means for storing a registered terminal management list including information on the number of hops for each mobile terminal accessing the wired network via its own station;
When the terminal registration request message is received from another base station, the mobile terminal identifier and hop number counter information set in the terminal registration request message and the terminal registration request message are directly transferred to the own station. A list management means for associating with the identifier information of the other base station and writing to the registered terminal management list in the storage means provided in the local station;
Transfer means for incrementing and transferring the value of the hop number counter included in the terminal registration request message received by the list management means of the local station;
Priority control means for performing priority control of radio packets destined for each mobile terminal based on the number of hops of the mobile terminal indicated by the registered terminal management list in the storage means included in the local station;
The gateway access point is
Storage means for storing a registered terminal management list including information on the number of hops for each mobile terminal accessing the wired network via its own station;
When the terminal registration request message is received from another base station, the mobile terminal identifier and hop number counter information set in the terminal registration request message and the terminal registration request message are directly transferred to the own station. A list management means for associating with the identifier information of the other base station and writing to the registered terminal management list in the storage means provided in the local station;
Priority control means for performing priority control of radio packets destined for each mobile terminal based on the number of hops of the mobile terminal indicated by the registered terminal management list in the storage means provided in the own station;
A wireless packet communication system. The transmission means of each of the base stations, when recognizing that the mobile terminal belonging to the own station has disconnected, transmits a terminal deletion request message in which the identifier of the mobile terminal is set,
When receiving the terminal deletion request message from another base station, the list management means of the base station serving as a relay station receives the terminal deletion request message from the registered terminal management list in the storage means included in the local station. Delete the information corresponding to the mobile device identifier set in
The transfer means of the base station serving as a relay station transfers the terminal deletion request message received by the list management means included in the own station,
When the gateway access point list management means receives the terminal deletion request message from another base station, it is set in the terminal deletion request message from the registered terminal management list in the storage means provided in the local station. Delete the information corresponding to the identifier of the mobile terminal
The wireless packet communication system according to claim 1. The base station
A database for storing parameters related to the operation of the local station, including at least information on identifiers of mobile terminals belonging to the local station;
The transmission means of the base station is
By periodically accessing the database and comparing the parameter with the previous access, the increase or decrease of the mobile terminal belonging to its own station is recognized. Create and send a device registration request message, and if there are fewer mobile terminals, create and send a terminal delete request message for that mobile terminal,
The wireless packet communication system according to claim 2. The transmission means of the base station is
Create and send a terminal registration request message triggered by the recognition that the connection process with the mobile terminal has been completed, and create and send a terminal delete request message triggered by the completion of the disconnection process with the mobile terminal To
The wireless packet communication system according to claim 2. In a wireless packet communication method used in a wireless packet communication system for transmitting and receiving wireless packets between a plurality of base stations,
The base station to be a relay station from the base station to which a mobile terminal belongs to a gateway access point that is the base station connected to a wired network, and the gateway access point is:
For each mobile terminal accessing the wired network via its own station, a registered terminal management list including information on the number of hops, which is the number of base stations that perform relay processing between the mobile terminal and the local station, is stored Storage means for
Each said base station
When the mobile terminal recognizes that it belongs to its own station, it transmits a terminal registration request message in which the identifier of the mobile terminal and information on the hop number counter used for measuring the number of hops to the local station are set. And
The base station to be a relay station
The terminal registration request message is received from another base station, the mobile terminal identifier and the hop number counter information set in the terminal registration request message, and the other that directly transfers the terminal registration request message to the own station In association with the identifier information of the base station of the base station, write to the registered terminal management list in the storage means provided in the own station,
Transfer the hop number counter value included in the received terminal registration request message by incrementing by 1,
The gateway access point is
The terminal registration request message is received from another base station, the mobile terminal identifier and the hop number counter information set in the terminal registration request message, and the other that directly transfers the terminal registration request message to the own station In association with the identifier information of the base station of the base station, while writing to the registered terminal management list in the storage means provided in the own station,
The base station serving as the gateway access point and relay station,
Priority control of radio packets destined for each mobile terminal is performed based on the number of hops of the mobile terminal indicated by the registered terminal management list in the storage means included in the local station.
A wireless packet communication method. When each of the base stations recognizes that the mobile terminal belonging to the mobile station has disconnected, the base station transmits a terminal deletion request message in which the identifier of the mobile terminal is set,
The base station to be a relay station is
The terminal deletion request message is received from the other base station, and the information corresponding to the identifier of the mobile terminal set in the terminal deletion request message is deleted from the registered terminal management list in the storage means included in the local station And
Forward the received device deletion request message,
The gateway access point is
The terminal deletion request message is received from the other base station, and the information corresponding to the identifier of the mobile terminal set in the terminal deletion request message is deleted from the registered terminal management list in the storage means included in the local station To
The wireless packet communication method according to claim 5. The base station
It has a database for storing parameters related to the operation of the own station, including at least information on the identifier of the mobile terminal belonging to the own station,
By periodically accessing the database and comparing the parameter with the previous access, the increase or decrease of the mobile terminal belonging to its own station is recognized. Create and send a device registration request message, and if there are fewer mobile terminals, create and send a terminal delete request message for that mobile terminal,
The wireless packet communication method according to claim 6. The transmission means of the base station is
Create and send a terminal registration request message triggered by the recognition that the connection process with the mobile terminal has been completed, and create and send a terminal delete request message triggered by the completion of the disconnection process with the mobile terminal To
The wireless packet communication method according to claim 6.

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