JP2003249936A - Radio equipment, method for controlling channel thereof and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize radio equipment capable of ensuring satisfactory communication quality by taking into consideration a radio wave state between radio stations constituting a multihopping radio network and selecting a channel. <P>SOLUTION: This radio equipment is provided with a control part 10 for recording signal strength information indicating the receiving strength, at its own station, of a radio wave transmitted from an adjacent station with the signal strength information included in the adjacent station information, using a route search packet to search for a new route while giving priority to signal strength, receiving a route search packet to add information of its own station to the last of a relay station list of the route search packet, transferring the route search packet to the adjacent station, retrieving adjacent station information of its own station on the basis of a relay station list of the received route search packet, selecting the next relay station of its own station among adjacent stations while giving priority to the signal strength, obtaining an optimum relay route and notifying a transmission source of the route search packet of the obtained relay route. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is realized by using a wireless device provided in a plurality of wireless stations forming a multi-hop wireless communication network, a communication path control method therefor, and the wireless device using a computer. For computer programs for.

[0002]

2. Description of the Related Art In recent years, studies for realizing a multi-hop wireless communication network (hereinafter referred to as a multi-hop wireless network) have been made in various fields. A multi-hop wireless network enables direct communication between arbitrary devices of a plurality of wireless devices arranged in a local area (radius of several hundred meters), and between wireless devices that radio waves do not reach directly. It is a network in which wireless devices between them relay and enable mutual communication.

In a multi-hop wireless network, the range of radio waves of a wireless device varies depending on the surrounding conditions of each wireless device and the shape of the antenna. In addition, since a communication path can be established on the mesh in a range where mutual communication is possible due to the nature of radio, a complicated network topology is configured. Further, the wireless device includes a fixed terminal (fixed wireless station) whose position does not change and a mobile terminal (mobile wireless station) whose position changes. In addition, there are wireless devices that are always powered on and wireless devices that are not.
For example, when a wireless device is built into a fax machine or a refrigerator, the power is generally always on, but a notebook personal computer or a PDA (Personal Digital Assistant) is used.
s: When a wireless device is incorporated in a personal information device, the power is often turned on only when it is used.

As described above, the multi-hop wireless network is a network that is spontaneously constructed and its configuration dynamically changes, unlike a network that is constructed deliberately like a communication network of a telecommunications carrier or a company. Is. Therefore, the conventional communication route control method cannot perform sufficient route control. Therefore, conventionally, as a communication path control method suitable for a multi-hop wireless network, for example, a method of constructing a relay path between wireless devices that radio waves do not reach directly has been studied.

Communication route control methods include a static route control method and a dynamic route control method. In the static route control method, a network administrator specifies a route based on the network configuration. In this method, it is necessary to set all the route control devices in consideration of the route for each route control device. Also, when the network configuration changes, it is necessary to set a new route for each route control device.

On the other hand, in the dynamic route control method, the route control devices exchange route information with each other to automatically determine a route. This dynamic route control method includes a method using a distance vector type route control protocol and a method using a link state type route control protocol. One of the typical distance vector type route control protocols is called RIP (Routing Information Protocol). This RIP is set by the wireless device once every 30 seconds.
Each time, it transmits all the route information it has to the route control device connected to itself. The route control range is up to 15 hops. Further, when the number of selectable routes is large, it is slow to converge into one route, the load of the route control device is light, and it is suitable for a relatively small-scale network.

One of the typical link state type routing protocols is OSPF (Open Shortest Path).
First) is called. In this OSPF, all route control devices on the network have the same link state database. It is characterized in that the route selected by the cost value can be controlled, the load of the route control device is heavy, it is suitable for a relatively large-scale network, and the route converges quickly when the topology changes.

Specifically, as a conventional communication path control method, for example, a method described in Japanese Patent Laid-Open No. 2001-127797 is known. In this method, as in the case of the RIP, adjacent wireless stations exchange their own route information with each other, and the route with the smallest number of hops is adopted. In addition, a technology that uses the route in which the packet for route search reaches the destination wireless station earliest as the shortest route is "The
Dynamic Source Routing Protocol for Mobile AdHoc N
etworks, '' Josh Broch, David B. Johnson, & David A.
Maltz, IETF MANET Working Group INTERNET-DRAFT, 22
Oct. 1999.

[0009]

However, the above-mentioned conventional communication path control method has the following problems. First, in the method that uses the route with the smallest number of hops, the number of relay stages is small, but there is a possibility that a wireless station located at the boundary of the reach of radio waves emitted from a wireless station will be used as a relay station. In communication with wireless stations located at the boundary of the radio wave coverage, the radio wave condition tends to be unstable, which makes it impossible to send and receive packets normally, resulting in frequent packet retransmissions. However, there is a problem that the use efficiency of the network deteriorates. As a result, there are problems in communication quality, such as insufficient throughput and unstable communication.

For example, as shown in FIG. 1, it is assumed that a multi-hop wireless network is composed of five wireless stations 102 to 110. The boundary lines P102 to P110 are
The boundaries of the radio wave coverage of the wireless stations 102 to 110 are shown. Here, when the wireless station 102 communicates with the wireless station 108, since the wireless station 108 is located outside the range of the boundary line P102, relay by another wireless station is necessary. In this example, as a route from the wireless station 102 to the wireless station 108, a route from the wireless station 102 to the wireless station 108 via the wireless stations 104 and 106, or from the wireless station 102 to the wireless station 11 is used.
There is a route to the wireless station 108 via 0. However, if the path with the smallest number of hops is adopted among these paths, it becomes a path from the wireless station 102 to the wireless station 108 via the wireless station 110, and the wireless station 110 causes the boundary line P10.
The above problem occurs because it is located on the upper side. As described above, in the conventional method, since the route is selected without considering the radio wave condition between the wireless stations, it is impossible to secure good communication quality.

Next, in the method of adopting the route in which the packet for route search reaches the destination wireless station earliest, the shortest route at the time of route search is not always the shortest steady route, and it happens by chance. A situation may occur in which the route is simply selected. In wireless packet communication, in order to avoid contention between terminals during packet transmission, CSM is used.
It is common to use a collision prevention method such as an A / CS method. In this collision prevention method, the order of packet retransmission at the time of collision is determined by a random number. For this reason, the route that should originally be the shortest route is in the later order of packet retransmission due to the occurrence of collision, and the route may not be the shortest route at the time of route search, and another route may happen to be the shortest route. . Thus, there is a problem that the route that should originally be the shortest route is not adopted, and the optimal route cannot be selected.

Further, in the conventional method, there is a possibility that a mobile terminal or a terminal whose power is frequently turned on / off is selected as a relay station. For this reason, when the terminal is moved or the power is turned off, the relay route disappears, and as a result, route re-search occurs and a stable communication route cannot be secured, and good communication quality is maintained. Can't do it.

The present invention has been made in consideration of such circumstances, and an object thereof is to select a communication route in consideration of a radio wave condition between wireless stations forming a multi-hop wireless network and to perform a good communication. It is an object of the present invention to provide a wireless device that can ensure quality and a communication path control method thereof.

Further, according to the present invention, a radio station to be a relay station can be selected in consideration of stability as a relay station of a multi-hop radio network, a stable communication path can be secured, and good communication quality can be maintained. It is also an object to provide a wireless device and a communication path control method therefor.

Another object of the present invention is to provide a computer program for realizing the wireless device by using a computer.

[0016]

In order to solve the above-mentioned problems, the wireless device according to claim 1 is provided in a plurality of wireless stations constituting a multi-hop wireless communication network, and has a packet communication function and a packet communication function. Has a packet relay function,
In a wireless device that sends and receives packets to and from a communication partner located outside the radio range of the local station via another station, the signal strength information indicating the reception strength of the radio wave transmitted from the adjacent station at the local station is displayed. Neighboring station information recording means for recording in the station information, route searching means for searching for a new route using the route search packet in signal strength priority, and relay station list of the route search packet for receiving the route search packet Of the own station is added to the end of the information of the own station, based on the transfer means for transferring the route search packet to the adjacent station and the relay station list of the received route search packet A route determining means for selecting the next relay station of its own station from the adjacent stations in priority of strength and determining an optimum relay route, and a route notifying means for notifying the source of the route search packet of the obtained relay route. Be prepared It is a symptom.

A radio apparatus according to a second aspect is provided in a plurality of radio stations forming a multi-hop type radio communication network, has a packet communication function and a packet relay function, and is outside the radio wave reachable range of the own station. In a wireless device that sends and receives a packet to and from a communication partner located through another station, an adjacent station information recording unit that records the registration date and time of a new adjacent station in the adjacent station information and a new route search packet is used. Means for searching for a different route with priority over the lifetime, and a route search packet that receives the route search packet, adds its own information to the end of the relay station list of the route search packet, and transfers the route search packet to an adjacent station. Based on the transfer means and the relay station list of the received route search packet, the neighboring station information of the own station is searched, and the next relay station of the own station is selected from among the neighboring stations with the lifetime priority, and the optimum. A route determining means for determining a relay route,
The present invention is characterized by including a route notification means for notifying the originator of the route search packet of the obtained relay route.

In the wireless device according to the present invention, there is provided information providing means for providing the neighboring station information to another station, and new station detecting means for detecting a new station based on the neighboring station information of the other station. It is further characterized by being equipped.

In the wireless device according to the fourth aspect, the transfer means avoids the duplicate transfer of the route search packet based on the adjacent station information of the source station of the route search packet and the adjacent station information of its own station. As described above, the transfer destination of the route search packet is selected.

A communication path control method according to a fifth aspect is provided in a plurality of wireless stations forming a multi-hop type wireless communication network, has a packet communication function and a packet relay function, and has a radio wave coverage of its own station. A communication partner located outside is a communication path control method in a wireless device that sends and receives packets via another station, and uses signal strength information indicating the reception strength at the local station of a radio wave transmitted from an adjacent station, The process of recording in the neighboring station information, the process of searching for a new route by using the route search packet in signal strength priority, and the step of receiving the route search packet and adding it to the end of the relay station list of the route search packet Information is added, the route search packet is transferred to the adjacent station, and the adjacent station information of the own station is searched based on the relay station list of the received route search packet, and the signal strength is given priority. Select the next relay station of the own station from among the neighbor station is characterized by comprising the steps of obtaining an optimum relay route, and a step of notifying the determined relay route to the originator of the route search packet.

A communication path control method according to a sixth aspect is provided in a plurality of wireless stations forming a multi-hop type wireless communication network, has a packet communication function and a packet relay function, and has a radio wave coverage of its own station. A communication route control method in a wireless device that sends and receives a packet via another station to a communication partner located outside, and a process of recording the registration date and time of a new adjacent station in the adjacent station information and a route search. The process of searching for a new route using a packet with priority over the lifetime, and the process of receiving a route search packet and adding its own information to the end of the relay station list of the route search packet Forwarding process and the relay station list of the received route search packet, the neighboring station information of the own station is searched, and the next relay station of the own station is selected from among the neighboring stations with the lifetime priority. A process of obtaining an optimum relay route is characterized by comprising the steps of notifying the determined relay route to the originator of the route search packet.

The communication path control method according to claim 7 further includes the step of providing the neighboring station information to another station and the step of detecting a new station based on the neighboring station information of the other station. Characterize.

In the communication route control method according to the present invention, the duplicate transfer of the route search packet is avoided based on the neighboring station information of the source station of the route search packet and the neighboring station information of its own station. The transfer destination of the route search packet is selected.

A computer program according to a ninth aspect is provided in a plurality of wireless stations forming a multi-hop type wireless communication network, has a packet communication function and a packet relay function, and is outside the radio wave reachable range of the own station. The communication partner located is a computer program for performing communication path control processing in a wireless device that transmits and receives packets via other stations, and the signal strength indicating the reception strength at the local station of the radio wave transmitted from the adjacent station. A process of recording information by including it in the neighboring station information, a process of searching for a new route by using a route search packet with signal strength priority, and a process of receiving the route search packet and checking the relay station list of the route search packet. Finally, based on the processing of adding the information of the own station and transferring the route search packet to the adjacent station, and the relay station list of the received route search packet. Search for neighboring station information of your own station, select the next relay station of your own station from neighboring stations with priority on signal strength, find the optimum relay route, and send the route search packet to the obtained relay route. It is characterized in that the computer is caused to execute the process of notifying the original. This allows the above-mentioned wireless device to be realized using a computer.

A computer program according to a tenth aspect is provided in a plurality of wireless stations forming a multi-hop type wireless communication network, has a packet communication function and a packet relay function, and is located outside the radio wave reachable range of the own station. The communication partner located is a computer program for performing communication path control processing in a wireless device that transmits and receives packets via another station, and processing for recording the registration date and time of a new adjacent station in the adjacent station information. And a process for searching for a new route with a lifetime priority using a route search packet, adding the information of the own station to the end of the relay station list of the route search packet by receiving the route search packet, and performing the route search Based on the process of transferring the packet to the adjacent station and the relay station list of the received route search packet, the adjacent station information of the own station is searched and the lifetime is excellent. Select a relay station next to your own station from among the adjacent stations, and ask the computer to execute the process of finding the optimum relay route and the process of notifying the sender of the route search packet of the obtained relay route. It has a feature. This allows the above-mentioned wireless device to be realized using a computer.

[0026]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In the following description, the communication path is simply called a path. FIG. 2 is a block diagram showing the configuration of the wireless device according to the embodiment of the present invention. The wireless device in FIG. 2 is included in a wireless terminal (wireless station).
A multi-hop wireless network as shown in FIG. 1 is configured by a plurality of wireless stations equipped with this wireless device. The wireless device in FIG. 2 has a packet communication function and a packet relay function, and transmits / receives packets to / from a communication partner located outside the radio wave coverage of its own station via another station.

The radio apparatus shown in FIG. 2 has an antenna 2, a radio transmission section 4, a radio reception section 6, a calculation section 8 and a control section 10.
And a main storage unit 12, a keyboard 14, a display 16, and an auxiliary storage unit 18.

The radio receiving section 4 receives a radio signal via the antenna 2 which transmits and receives radio waves, demodulates it and A / D converts it to obtain packet data contained in the radio signal. The wireless reception unit 4 stores this packet data in the main storage unit 12. The calculation unit 8 analyzes the packet data stored in the main storage unit 12 and notifies the control unit 10 when the packet data is data for route control. The control unit 10 uses this route control data to perform route control processing. In addition, the control unit 1
0 has a packet communication function and a packet relay function.

The keyboard 14 is an input device and is capable of command input and data input. The display 16 is a display device and displays a message or the like. Control unit 1
0 indicates that when the route control data requires relay processing, the data is converted into a packet of a predetermined format and the wireless transmission unit 6
Output to. Further, the data input from the keyboard 14 and the transmission data generated in the local station are also output to the wireless transmission unit 6 as packets. The wireless transmission unit 6 performs D / A conversion on the received packet data and further converts the packet data by a modulation method such as spread spectrum modulation, and then the antenna 2
To send via.

The arithmetic unit 8 and the control unit 10 are composed of a CPU (central processing unit), and the programs for realizing the functions of the respective units 8 and 10 are loaded into the main storage unit 12 and executed to execute their functions. Is realized. The auxiliary storage device 18 stores the programs (OS (operating system) and application programs), and the programs are stored in the main storage unit 12 when the wireless device is activated.
Loaded in.

The wireless device shown in FIG. 2 can be provided in various electronic devices such as a fax machine, a refrigerator, a notebook personal computer, a PDA and the like.

Next, the route control processing performed by the control unit 10 of the wireless device shown in FIG. 2 will be sequentially described. First, the types of route control packets used by the control unit 10 in the route control process will be described. 3 to 7 are diagrams showing format examples of each route control packet. There are five types of route control packets: beacon packets, route search packets, route notification packets, adjacent station confirmation packets, and route deletion packets.

The beacon packet has a format shown in FIG. 3 and is transmitted periodically. This beacon packet notifies other stations of the existence of the own station, and also provides other stations with information of wireless stations that can be directly connected to the own station. In FIG. 3, the destination address is set to a predetermined value for addressing all other stations as the address of the wireless station that receives the packet. As the source address, the address of the local station is set as the address of the wireless station that transmitted the packet. The address of the wireless station that relayed the packet is set in the relay station address. A predetermined value indicating a beacon packet is set in the packet type. Hop limits include
Set the maximum number of times a packet can be relayed. This hop limit value is decremented by 1 by the relay station each time it is relayed, and when it is 0, it is not relayed.

The beacon cycle is set to the beacon packet transmission cycle. After the beacon period, the neighboring station information of the own station is set as the neighboring station list. As the adjacent station information, information on registered stations registered in an adjacent station database (adjacent station DB) described later is used. In particular,
It is an adjacent station address, signal strength, and registration date and time. The adjacent station address is an address of a wireless station with which the local station can directly communicate. The signal strength is the reception strength at the local station of the radio wave transmitted from the adjacent station. The registration date and time is the date and time when the adjacent station is newly registered.

The route search packet has a format shown in FIG. 4, and is used to detect a route to another wireless station. In FIG. 4, the destination address, the source address, the relay station address, the packet type, and the hop restriction are the same as those in the above beacon packet. However, the address of a specific wireless station is set as the destination address, and the packet type is set to route search.

In the path policy, either "signal strength priority" or "lifetime priority" is set. The lifetime is the period during which the wireless station is operating continuously. An option parameter for each route policy is set in the route policy option. When the signal strength is prioritized, a signal strength threshold is set, and a wireless station having a signal strength equal to or higher than this threshold becomes a candidate for a relay station. In the case of prioritizing the survival period, a period threshold is set, and a wireless station with a survival period equal to or greater than this threshold becomes a candidate for a relay station. For the relay station address in the relay station list,
The station that relayed the packet sets its address when relaying.

The route notification packet has a format shown in FIG. 5, and is used for a response to the route search packet. The route notification packet notifies the source of the route search packet of the route to the own station. In FIG. 5, the content of the route notification packet is the same as that of the route search packet. However, the packet type is route notification. The relay station address group constitutes an address list (relay route list) of relay stations on the route from the destination address station to the source address station. The contents of the relay route list are appropriately edited according to the route policy by each wireless station on the way of returning, based on the address list of the relay station recorded in the route search packet.

The adjacent station confirmation packet is a packet of the format shown in FIG. 6, and is used to confirm whether or not the adjacent station can directly communicate. In FIG. 6, the destination address, the source address, the relay station address, the packet type, and the hop limit are the same as those of the packet. However, the packet type is the adjacent station confirmation, and the hop limit value is 1
And The confirmation request source sets a predetermined value in REQ.
In the ACK, the station that receives the confirmation request sets a predetermined value when responding.

The route deletion packet is a packet of the format shown in FIG. 7, and is used to notify that the route between the stations has disappeared. In FIG. 7, destination address, source address, relay station address, packet type,
The hop limit is the same as the above packet. However, the packet type is set to route deletion. For the deleted station address, set the address of the lost station (deleted station). For the detected station address, set the address of the station (detected station) that detected the deleted station. This indicates that the route between the deleted station and the detected station is lost. For the relay station address, the station that relayed the route deletion packet sets its own address when relaying.

Next, the database provided in the wireless device shown in FIG. 2 will be described. The wireless device includes three databases: an adjacent station database (adjacent station DB), a relay route database (relay route DB), and a packet relay record database (packet relay record DB). The contents of these databases are stored in the main storage unit 12, and the control unit 10 updates the contents of each database.

The adjacent station DB is a database for recording information of adjacent stations, and FIG. 8 shows an example of the recording configuration of one adjacent station. In FIG. 8, the address of the adjacent station to be recorded is recorded in the station address. As the signal strength, the reception strength at the local station of the radio wave transmitted from the recording target adjacent station is acquired from the wireless reception unit 4 and recorded. At the time of new registration,
Record the date and time when the adjacent station to be recorded is newly registered. As the update date and time, the date and time when the recorded content regarding the recording target adjacent station is updated is recorded. In the temporary registration flag, when it is unconfirmed that the recording target adjacent station and the local station can communicate with each other, a flag indicating this unconfirmed state is recorded. In the asymmetric station flag, a flag indicating this asymmetric state is recorded when only a beacon packet from any one of the stations between the recording target adjacent station and the own station arrives.

In the beacon cycle, the beacon packet transmission cycle in the recording target adjacent station is recorded. The recorded contents (adjacent station address, signal strength, registration date and time) after the beacon period are information about the adjacent station of the recording target adjacent station,
It is acquired by the beacon packet received from the recording target adjacent station. Then, in the adjacent station address, the address of the adjacent station for the recording target adjacent station is recorded. As the signal strength, the signal strength of the adjacent station for the recording target adjacent station is recorded. As the registration date and time, the registration date and time of the adjacent station for the recording target adjacent station is recorded.

The relay route DB is a database for recording a route to a wireless station which requires relay by another station, and FIG. 9 shows a recording configuration example of one route. In FIG. 9, the address of the destination wireless station is recorded in the wireless station address. The date and time when the route is newly registered is recorded in the new registration date and time. As the update date and time, the date and time when the recorded content regarding the route is updated is recorded. In the route policy, the route policy used when selecting the route is recorded. In the relay station address in the relay route list, the address of the wireless station (relay station) that passes through to the destination wireless station is recorded.

The packet relay record DB is a database for recording the contents of packet relay, and is shown in FIG.
Shows an example of the recording configuration of one relay content. However, the content regarding the route search packet or the route deletion packet is the recording target. In FIG. 10, the type of the relayed packet (route search or route deletion) is recorded in the packet type. In the wireless station address, the address of the source station of the relayed packet is recorded. The relay date and time records the date and time when the packet was relayed.

Next, with reference to FIG. 11, an operation in which the wireless device of FIG. 2 acquires information on a route to another wireless station in the multi-hop wireless network by the route control processing of the control unit 10 will be described. . FIG. 11 is a schematic flowchart showing the flow of processing until the wireless device shown in FIG. 2 acquires route information. First, in the beacon transmission / reception phase, a wireless station (new station) that newly joins the multi-hop wireless network sends out a beacon packet in order to acquire information about an adjacent station. Also, the wireless stations that have already participated periodically send out beacon packets to indicate the existence of their own stations (step S1).

In step S2, the wireless station receiving the beacon packet searches the adjacent station DB and the relay route DB of its own station, and if there is no data related to the beacon packet transmitting station, judges the transmitting station as a new station. Then, the transmitting station is temporarily registered in the adjacent station DB (the temporary registration flag is set here). Further, the wireless station that has received the beacon packet from the new station also transmits the beacon packet from itself. The new station receives this beacon packet, acquires information about the adjacent station, and registers it in the adjacent station DB. On the other hand, if there is data from the beacon packet transmitting station, the corresponding data in the adjacent station DB is updated according to the content of the received beacon packet.

Next, in the adjacent station confirmation phase, the wireless station that receives the beacon packet from the new station sets REQ to confirm whether mutual communication is possible with the beacon packet transmitting station. And transmits an adjacent station confirmation packet to the beacon packet transmitting station (step S
3). The beacon packet transmitting station which has received the adjacent station confirmation packet sets ACK and returns the adjacent station confirmation packet (step S4). This response packet (AC
When receiving the neighbor station confirmation packet with K set,
The wireless station that is the source of the adjacent station confirmation packet resets the temporary registration flag in the adjacent station DB (step S5).

The beacon transmission / reception phase and the adjacent station confirmation phase will be specifically described with reference to FIG. In FIG. 12, station X is a new station, and the contents of its adjacent station DB and relay route DB are empty. This X station transmits a beacon packet, and the existing station A receives the beacon packet (step S11). Here, station A is the adjacent station DB of its own station.
Since there is no data regarding the X station in the relay route DB, the X station is judged as a new station, the X station is temporarily registered in the adjacent station DB, and the temporary registration flag is set. Furthermore, B of the adjacent station DB,
A beacon packet in which data of stations C and D is recorded is transmitted (step S12), and an adjacent station confirmation packet (REQ set) addressed to the station X is transmitted (step S13).

Upon receiving the beacon packet in step S12, the X station temporarily registers the A station in the adjacent station DB of its own station based on the contents of this beacon packet. Where B,
The C and D station data are recorded as the adjacent station data of the A station, and the temporary registration flag is set. Further, an adjacent station confirmation packet (REQ set) addressed to station A is transmitted (step S15).

When the X station receives the adjacent station confirmation packet (REQ set) in step S13, it sets ACK and returns the adjacent station confirmation packet (step S1).
4). Upon receiving the adjacent station confirmation packet (ACK set), the station A resets the temporary registration flag of the station X temporarily registered in the adjacent station DB so that mutual communication is possible with the station X.

When the station A receives the adjacent station confirmation packet (REQ set) in step S15, it sets ACK and returns the adjacent station confirmation packet (step S1).
6). Upon receiving the adjacent station confirmation packet (ACK set), the X station resets the temporary registration flag of the A station temporarily registered in the adjacent station DB so that mutual communication with the A station is possible.

Station A does not send back the adjacent station confirmation packet (ACK set) in step S14 even after a predetermined time has elapsed, and receives the adjacent station confirmation packet (REQ set) from station X in step S15. In this case, it is determined that only one-way communication can be performed, and the asymmetric flag of the X station in the adjacent station DB is set. Similarly, the X station operates in step S16.
Neighbor confirmation packet (ACK set) of is not returned,
Further, when the adjacent station confirmation packet (REQ set) from the station A in step S13 is received,
Set the station's asymmetric flag. In this way, the reason why only one-way communication is possible is that the other station cannot receive the radio wave emitted from its own station because the other station is located near the boundary of the radio range. It is possible that

Next, the route construction phase of FIG. 11 will be described. The wireless station which has received the beacon packet adds the adjacent station D of its own station to the adjacent station list of the received beacon packet.
When data regarding an unregistered adjacent station is found in B and the relay route DB, a route search packet is transmitted to the adjacent station that is the source of this beacon packet (step S6). Here, a route policy and a hop limit value are set in the route search packet.

For example, as shown in FIG. 13, station A receives a beacon packet from an adjacent station X (step S2).
1). The content of the adjacent station DB of the X station is recorded in the adjacent station list of the beacon packet, and includes the data of the Y station that is not registered in the adjacent station DB of the A station and the relay route DB. When station A finds data on station Y in the neighbor station list of the received beacon packet, station A sends a route search packet to station X (step S22).

Upon receiving this route search packet, the X station, if within the hop limit range of the route search packet (the hop limit value is 1 or more), relays the route search packet. Here, the relay process of the route search packet will be described with reference to the relay example of FIG.

In FIG. 14, station A receives a route search packet transmitted from a certain source station, and if it is within the hop limit of this route search packet, station A sends the route search packet to the adjacent station of its own station. Forward to. Here, the transfer destination is determined as follows. The wireless station that has received the route search packet excludes the adjacent station common to the route search packet transmission source station and the own station from the registered stations in the adjacent station DB of the own station,
Ask for the remaining neighbors. Further, of the remaining adjacent stations, a station that is not in the relay station list of the route search packet is selected as the transfer destination.

When relaying, when relaying a route search packet, station A sets its own address as the relay station address for the route search packet to be transferred, and further, at the end of the relay station list. Add your own address and subtract 1 from the hop limit value to set. Then, the relay contents are recorded in the packet relay record DB of the own station.

In the example of FIG. 14, station A transfers the received route search packet to station B and station C as route search packets PKT1 and PKT2, respectively. Then, station B
The route search packet PKT1 is relayed, but here, only station D is selected as the transfer destination. This is the adjacent station D of station B
Since the data of the C station exists in the data of the A station of B, the C station is because the C station is a common adjacent station of its own station (B station) and the route search packet transmission source station (A station). In this way, when the route search packet transmission source station and the adjacent station of the own station are adjacent to each other, it is determined that the transfer to the adjacent station is unnecessary. Similarly, station C relays the route search packet PKT2, but selects only station D as the transfer destination and does not transfer it to station B.

Then, station D receives the route search packet PKT.
When 1 is received, the transfer destination is similarly determined to the E station and the F station, and the route search packet PKT1 is transferred to each station.
Further, the D station also continuously receives the route search packet PKT2. In this way, when a plurality of route search packets transmitted from the same station are received within a predetermined time, the second and subsequent route search packets are not relayed. Therefore, station D
The route search packet PKT2 is not transferred. Next, the E station and the F station respectively receive the route search packet P
It receives KT1 and transfers it to the G station.

Further, the wireless station having received the route search packet creates a route notification packet based on the contents of the route search packet and transmits it to the source station of the route search packet. Here, a method of creating a route notification packet will be described.
When the route notification packet is created, the relay route list describing the relay route notified to the route search packet source station is edited based on the relay station list of the route search packet.
This editing method differs depending on the route policy of the route search packet. Further, the same contents as the route policy of the route search packet are set in the route policy of the route notification packet.

First, the case where the path policy is "signal strength priority" will be described with reference to FIG. In FIG. 15, station Z receives a route search packet and creates a route notification packet. Further, the route policy of the route search packet is “signal strength priority”, and the signal strength threshold of the route policy option is “6”.

When the Z station receives the route search packet,
From the adjacent station DB of the own station, the signal strength is the signal strength threshold “6”.
The above-mentioned recording target stations are searched. In the example of FIG. 15, F
The station, the H station, the R station, and the Y station correspond and satisfy the signal strength threshold condition. Next, a station having a station in the relay station list of the route search packet as an adjacent station and having a signal strength with the station satisfying the signal strength threshold value condition is searched from these stations. In the example of FIG. 15, the R station has a route to the V station, and the signal strength between the V stations is 6, which satisfies the condition. Further, the Y station has a route to the X station, and the signal strength between the X stations is 6, which satisfies the condition.

Then, a station having a route to a station closer to the route search packet transmission source station (this station is referred to as "target list station") is selected from the R station and the Y station. Figure 15
In the example, since the V station is closer to the route search packet transmission source station than the X station, the R station having the V station as an adjacent station is selected.

Here, when it is not possible to narrow down to one station and there are a plurality of candidates, the sum of the signal strength between the local station and the adjacent station and the signal strength between the adjacent station and the target list station is the maximum. Select the adjacent station. Furthermore, if multiple candidates remain,
One station is selected by a predetermined method (for example, using a random number).

Then, the contents of the relay station list of the route search packet are edited so that the selected one adjacent station (R station) becomes the next relay station of the own station (Z station) and the relay of the route notification packet is performed. Create a route list. In the example of FIG. 15, the relay route list is edited so that the relay route extends from the V station to the R station and then to the Z station.

If there is no corresponding adjacent station, the contents of the relay station list of the route search packet remain unchanged,
This is the relay route list of the route notification packet.

Next, referring to FIG. 16, a case where the route policy is "lifetime priority" will be described. In FIG. 16, the Z station receives the route search packet and creates a route notification packet. Further, the route policy of the route search packet is "lifetime priority", and the period threshold of the route policy option is "24 hours".

When the Z station receives the route search packet,
From the adjacent station DB of its own station, a recording target station whose lifetime is equal to or longer than the period threshold value “24 hours” is searched. In the example of FIG. 16, it is 15:00 on December 12, 2001, and F station, H
Stations, K stations, and Y stations have passed 24 hours or more from the registration date and time, and satisfy the lifetime threshold condition. If there is no corresponding station, the value of the period threshold value is decreased by, for example, 20%, and the search is performed again until it is found.

Then, a station having a station in the relay station list of the route search packet as an adjacent station is searched from the found stations. In the example of FIG. 16, station K has a route to station V and satisfies the condition. Also, the Y station has a route to the X station and satisfies the condition. If there is no station satisfying the condition here, the process is repeated from the search process of the station satisfying the above-mentioned lifetime threshold value condition (re-search while lowering the value of the period threshold value by 20%, for example).

Next, from these K station and Y station, a station having a route to a station closer to the route search packet source station (target list station) is selected. In the example of FIG. 16, since the V station is closer to the route search packet transmission source station than the X station,
Select K station that has a station as an adjacent station.

Here, when it is not possible to narrow down to one station and there are a plurality of candidates, one station is selected in the same manner as in the case of "signal strength priority".

Then, the contents of the relay station list of the route search packet are edited so that the selected one adjacent station (K station) becomes the next relay station of the own station (Z station), and the route notification packet is relayed. Create a route list. In the example of FIG. 16, the relay route list is edited so that the relay route extends from the V station to the K station and then to the Z station.

If there is no corresponding adjacent station, the contents of the relay station list of the route search packet remain unchanged.
This is the relay route list of the route notification packet.

The wireless station having received the route search packet creates a route notification packet as described above and transmits this route notification packet to the relay station next to itself. Figure 15
In this example, the Z station transmits the route notification packet to the R station. Further, in the example of FIG. 16, the Z station transmits the route notification packet to the K station.

Upon receiving the route notification packet, the wireless station edits the relay route list of the route notification packet according to the route policy of the route notification packet, as in the case of editing the relay route list described above. Then, the route notification packet having the edited relay route list is transmitted to the next relay station of the own station.

In this way, the route notification packet is sequentially delivered to the route search packet source station via the relay station while the contents of the relay route list are being rewritten (step S7 in FIG. 11). The route search packet transmission source station determines each wireless station within the hop limit from its own station (each station from the beginning to the end of the relay route list) according to the relay station and the order in which they are listed in the relay route list of this route notification packet ) You can know the route to. The relay route DB of the own station is updated according to this route information (step S
8).

Next, the operation of the wireless device of FIG. 2 for deleting a route by the route control processing of the control unit 10 will be described. When a beacon packet does not arrive from a specific adjacent station for a predetermined period or longer, the wireless station transmits an adjacent station confirmation packet to the adjacent station. Then, when there is no response to the adjacent station confirmation packet, the data regarding the adjacent station is deleted from the adjacent station DB and the relay route DB of the own station. Further, a route deletion packet recording the deleted contents is transmitted. For this destination, a station different from the station adjacent to the deleted adjacent station is selected from the adjacent stations of the own station.

Further, when there is a relay route in the relay route DB that includes the deleted station as a relay station, a route search packet is transmitted for re-searching the corresponding relay route. If this destination has a neighboring station that is common to the station that is adjacent to the deleted neighboring station among the neighboring stations of the own station, the station that has the largest number of neighboring stations that are not common to the own station is selected. on the other hand,
If the deleted adjacent station has no adjacent station common to the adjacent station, the adjacent station of the own station having the largest number of adjacent stations not common to the own station is selected.

When the wireless station having received the route deletion packet has a relay route including the deleted station as a relay station in the relay route DB, the wireless station deletes the relay route and re-searches for the corresponding relay route. For sending a route search packet. For this destination, the station that relayed the route search packet to itself is set. Next, the relay processing of the route deletion packet is performed. This relay process is performed in the same procedure as the above-described route search packet relay method.

According to the above-described embodiment, since the route search can be performed by prioritizing the signal strength, the communication route is selected in consideration of the radio wave condition between the wireless stations forming the multi-hop wireless network, and the good communication is performed. The effect that the quality can be secured is obtained.

Further, since the route search can be performed by prioritizing the lifetime, the wireless station to be the relay station is selected in consideration of the stability as the relay station of the multi-hop wireless network, and the stable communication route is secured. It is also possible to obtain an effect that good communication quality can be maintained.

Further, since the neighboring station information is provided to another station by using the beacon packet and the new station is detected based on the neighboring station information of the other station, a route search is appropriately performed by obtaining a trigger for searching a new communication route. It can be carried out.

Further, the transfer destination of the route search packet is selected based on the adjacent station information of the source station of the route search packet and the adjacent station information of its own station so as to avoid the duplicate transfer of the route search packet. , The route can be searched efficiently.

Further, by recording a program for realizing the function of the control unit shown in FIG. 2 in a computer-readable recording medium and reading the program recorded in this recording medium into a computer system and executing it. Route control processing may be performed. The "computer system" may include an OS and hardware such as peripheral devices. In addition, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. Further, the “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system.

Further, the "computer-readable recording medium" means a volatile memory (RAM) inside a computer system which serves as a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. ), Which holds the program for a certain period of time. The program may be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. Further, the program may be a program for realizing some of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present invention. included.

[0087]

As described above, according to the present invention,
Since the route can be searched by prioritizing the signal strength,
The effect that the communication path can be selected in consideration of the radio wave condition between the wireless stations that form the multi-hop wireless network and good communication quality can be secured is obtained.

Further, according to another invention, since the route search can be performed by prioritizing the lifetime, the wireless station to be the relay station is selected in consideration of the stability as the relay station of the multi-hop wireless network, The effect that a stable communication path can be secured and good communication quality can be maintained is obtained.

Further, since the neighboring station information is provided to another station and a new station is detected based on the neighboring station information of the other station, it is possible to carry out a route search as appropriate with a new communication route search trigger.

Further, the transfer destination of the route search packet is selected based on the adjacent station information of the source station of the route search packet and the adjacent station information of the own station so as to avoid the duplicate transfer of the route search packet. , The route can be searched efficiently.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration example of a multi-hop wireless network.

FIG. 2 is a block diagram showing a configuration of a wireless device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a format example of a beacon packet.

FIG. 4 is a diagram showing a format example of a route search packet.

FIG. 5 is a diagram showing a format example of a route notification packet.

FIG. 6 is a diagram showing a format example of an adjacent station confirmation packet.

FIG. 7 is a diagram showing a format example of a route deletion packet.

FIG. 8 is a diagram showing a configuration example of an adjacent station database.

FIG. 9 is a diagram showing a configuration example of a relay route database.

FIG. 10 is a diagram showing a configuration example of a packet relay record database.

FIG. 11 is a schematic flowchart showing a flow of processing until the wireless device shown in FIG. 2 acquires route information.

FIG. 12 is a diagram for explaining the processing flow of the beacon transmission / reception phase and the adjacent station confirmation phase shown in FIG. 11.

FIG. 13 is a diagram for explaining the flow of processing in the route construction phase shown in FIG. 11.

FIG. 14 is a diagram showing a relay example for explaining a relay method of a route search packet.

FIG. 15 is a diagram showing an example of editing a relay route list for explaining a relay route determination method based on signal strength priority.

FIG. 16 is a diagram showing an example of editing a relay route list for explaining a relay route determination method based on lifetime priority.

[Explanation of symbols]

2 ... Antenna, 4 ... Radio transmitter, 6 ... Radio receiver, 8 ...
Calculation unit, 10 ... Control unit, 12 ... Main storage unit, 14 ... Keyboard, 16 ... Display, 18 ... Auxiliary storage unit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K030 GA02 HA08 JL01 KA05 LB05                       MD07                 5K033 AA02 AA09 BA01 BA11 CA06                       CB01 CB08 DA19 EA03 EA07                 5K067 AA23 CC08 CC10 DD44 EE02                       EE25 FF05 FF17 GG02 HH17                       HH22 HH23

Claims (10)

[Claims] 1. A plurality of wireless stations forming a multi-hop wireless communication network, having a packet communication function and a packet relay function, and being a communication partner located outside the radio wave coverage of the own station is another station. In a wireless device that transmits and receives packets via the adjacent station information recording means for recording the signal strength information indicating the reception strength of the radio wave transmitted from the adjacent station at the local station, and the route search. A route search means for searching a new route by using a packet in signal strength priority, a route search packet is received, information of the own station is added to the end of the relay station list of the route search packet, and the route search packet is Based on the transfer means for transferring to the adjacent station, and the adjacent station information of the own station based on the relay station list of the received route search packet, the next relay station of the own station is selected as the adjacent station among the adjacent stations with the signal strength given priority. And al selection, a route determining means for determining an optimal relay route, wireless devices and route notifying means for notifying the determined relay route to the originator of the route search packet, comprising the. 2. A multi-hop wireless communication network comprises a plurality of wireless stations, has a packet communication function and a packet relay function, and is a communication partner located outside the radio wave reachable range of the local station. In a wireless device that sends and receives a packet via, an adjacent station information recording unit that records the registration date and time of a new adjacent station in the adjacent station information, and a new route is searched with a lifetime search by using a route search packet. Route search means, a transfer means for receiving the route search packet, adding the information of the own station to the end of the relay station list of the route search packet, and transferring the route search packet to the adjacent station, and the received route Based on the relay station list in the search packet, search for neighboring station information of your own station, select the next relay station of your own station from the neighboring stations with priority on lifetime, and determine the optimal relay route. It means a wireless device which is characterized in that and a route notification unit configured to notify the determined relay route to the originator of the route search packet. 3. An information providing means for providing the neighboring station information to another station, and a new station detecting means for detecting a new station based on the neighboring station information of the other station. The wireless device according to claim 1 or 2. 4. The transfer means, based on the neighboring station information of the source station and the neighboring station information of the own station of the route search packet, avoids the duplicate transfer of the route search packet of the route search packet. The wireless device according to claim 3, wherein a transfer destination is selected. 5. A multi-hop wireless communication network is provided with a plurality of wireless stations, has a packet communication function and a packet relay function, and is a communication partner that is located outside the radio wave reachable range of the local station. A method of controlling a communication path in a wireless device for transmitting and receiving a packet via, comprising the step of recording the signal strength information indicating the reception strength at the local station of the radio wave transmitted from the adjacent station by including the signal in the adjacent station information. , A process of searching for a new route by using a route search packet in signal strength priority, and adding the information of the own station to the end of the relay station list of the route search packet by receiving the route search packet, To the adjacent station, and based on the relay station list of the received route search packet, the adjacent station information of the own station is searched, and the next relay station of the own station is selected from the adjacent stations by the signal strength priority. Selected, process and communication path control method characterized by comprising the steps, a to notify the determined relay route to the originator of the route search packet to find the optimal relay route. 6. A multi-hop wireless communication network is equipped with a plurality of wireless stations, has a packet communication function and a packet relay function, and is a communication partner that is located outside the radio wave reach of the other station. A method of controlling a communication route in a wireless device that transmits and receives a packet via a network, including a process of recording the registration date and time of a new adjacent station in the adjacent station information, and a new route using a route search packet. A process of preferentially searching, a process of receiving a route search packet, adding information of its own station to the end of the relay station list of the route search packet, and transferring the route search packet to an adjacent station, and the received route Based on the relay station list of the search packet, search the neighboring station information of its own station, select the next relay station of its own station from the neighboring stations with priority over the lifetime, and obtain the optimum relay route, Communication path control method characterized by comprising the calculated and the process of notifying the relay path to the originator of the route search packet, a. 7. The method according to claim 5, further comprising: providing the neighboring station information to another station, and detecting a new station based on the neighboring station information of the other station.
The communication path control method described in. 8. The transfer destination of the route search packet is selected based on the adjacent station information of the source station of the route search packet and the adjacent station information of the own station so as to avoid duplicate transfer of the route search packet. The communication path control method according to claim 7, wherein 9. A multi-hop type wireless communication network is equipped with a plurality of wireless stations, has a packet communication function and a packet relay function, and is a remote station that is a communication partner located outside the radio wave range of its own station. A computer program for performing a communication path control process in a wireless device that sends and receives packets via a wireless network device, wherein signal strength information indicating the reception strength at a local station of a radio wave transmitted from a neighboring station is added to the neighboring station information. The process of including and recording, the process of searching for a new route using the route search packet with signal strength priority, and the process of receiving the route search packet and adding the information of its own station to the end of the relay station list of the route search packet. Then, based on the processing of transferring the route search packet to the adjacent station and the adjacent station information of the own station based on the relay station list of the received route search packet, the signal strength superiority is searched. Select a relay station next to your own station from among the adjacent stations, and obtain the optimum relay route, and notify the computer of the route search packet of the obtained relay route. A computer program characterized by. 10. A multi-hop wireless communication network is equipped with a plurality of wireless stations, has a packet communication function and a packet relay function, and is a remote station that is a communication partner located outside the radio wave reachable range of the own station. A computer program for performing a communication route control process in a wireless device that transmits and receives a packet via, including a process of recording the registration date and time of a new neighboring station in the neighboring station information, and using a route search packet. A process of searching for a new route with priority over the lifetime, a process of receiving a route search packet, adding the information of its own station to the end of the relay station list of the route search packet, and forwarding the route search packet to an adjacent station Based on the relay station list of the received route search packet, the neighboring station information of the own station is searched, and the next relay station of the own station is selected from among the neighboring stations with the lifetime priority. And a process of obtaining the optimal relay route, the computer program characterized by executing a process of notifying the determined relay route to the originator of the route search packet, to the computer.