JP2000269985A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radio communication system that clearly decides network unit of a radio terminal so as to simply designate a specific radio terminal as a repeater and to obtain a communication system where a network can easily be extended by using the repeater. SOLUTION: A radio terminal collects a role and sub network ID information of a radio terminal in existence within a communication available range of its own terminal. When no center station is in existence in a communication available range, the radio terminal discriminates that it itself is a center station (step 502), decides a sub network ID and informs surrounding terminals of it. When a plurality of radio terminals using different sub networks are in existence in the communication available range, the radio terminal discriminates whether or not a relay recognizing all the sub networks is in existence (step 508), and when it is not in existence, the radio terminal itself acts as a relay station (step 509) and informs all the existing radio terminals about the change in the role of the radio terminal (step 514). The extension of the network is realized by deciding the role of a new radio terminal according to such a procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ad-hoc network composed of a plurality of wireless terminals, wherein each wireless terminal serves as a central station, a relay station, and a slave station and connects to an adjacent sub-network. About.

[0002]

2. Description of the Related Art Conventionally, as a form of a system in which a plurality of wireless terminals communicate with each other, for example, a "wireless LAN technology course" (supervised by Atsushi Matsushita and Hiroshi Shigeno, published on September 10, 1994, Soft Co., Ltd.)・ Published by Research Center, pp8
9-110), the MAC function in each wireless terminal,
A centralized control station that manages the equivalent distributed system having control functions such as station management, a MAC function, and a control function is installed, and a centralized system in which each station communicates via this central control station. The central control station performs only control necessary for wireless communication, and communication between stations is classified into three types of a hybrid system in which direct communication is performed.

In the centralized system and the hybrid system,
Although the basic service area can be widened compared to the peer-to-peer distribution method, a central control station must be installed even when two wireless terminals face each other, and each wireless terminal communicates with the central control station. Must be installed in the area. Also,
If a failure occurs in the central control station, all terminals will be unable to communicate. Therefore, when a temporary network is constructed, it is effective to employ a peer-to-peer distribution system.

[0004]

However, in the peer-to-peer distribution system, in order for a certain wireless terminal to directly communicate with another wireless terminal, they must be within a wireless communication range of each other. If this is not the case, it is necessary to appropriately select a relay terminal and exchange messages via the relay terminal. On the other hand, for example, in a wired network, since a wire is used as a communication medium,
The network unit is clearly defined, and the terminal that relays to another network is immediately determined at the initial input stage.

SUMMARY OF THE INVENTION It is an object of the present invention to clearly define a network unit of a wireless terminal and easily designate a specific wireless terminal as a repeater, and to easily extend a network by using the repeater. It is an object of the present invention to provide a communication system.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a wireless network composed of a plurality of wireless terminals, a central station being a wireless terminal forming a sub-network having a clear boundary, The relay station is a wireless terminal that connects a plurality of sub-networks, and the slave station is a wireless terminal that belongs to at least one of the sub-networks and does not belong to any of them.

As a result, the network unit of the wireless terminal becomes clear, a specific wireless terminal can be easily designated as a repeater, and the network can be easily expanded by using the repeater.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a radio network comprising a plurality of radio terminals, a central station which is a radio terminal forming a subnetwork having a clear boundary, A relay station that is a wireless terminal that connects the sub-networks, and a slave station that is neither of these but belongs to at least one sub-network. The unit becomes clear, a specific wireless terminal can be easily designated as a repeater, and the use of the repeater has an effect that network expansion can be easily performed.

The invention according to claim 2 is characterized in that, when an arbitrary wireless terminal detects that the central station is not present in the service area of the own terminal, the wireless terminal sets the own terminal as the central station. 2. The wireless communication system according to claim 1, wherein the presence / absence of a central station for determining a subnetwork unit is examined in a service area of the own station. By determining the sub-network ID and broadcasting it to the communicable range of the central station at the same time, the sub-network unit can be determined and the network unit can be clarified.

[0010] The invention according to claim 3 is characterized in that, when an arbitrary wireless terminal detects that the own terminal belongs to a plurality of sub-networks, the own terminal is set as a relay station. Item 1. The wireless communication system according to Item 1, wherein the wireless terminal investigates within its own service area, confirms presence from terminals belonging to at least two different sub-networks, and furthermore, If there is no terminal that can communicate with any of the terminals to which it belongs, the local station becomes a relay station, and broadcasts simultaneously to the communicable range of the central station and the local station. Has the effect that it is possible to connect at least two sub-networks.

[0011] According to a fourth aspect of the present invention, when a new wireless terminal enters a wireless network, the new wireless terminal searches in a service area of its own terminal, and based on the search result, the central station, the relay station, 2. The wireless communication system according to claim 1, wherein the new wireless terminal is set in any of the slave stations, wherein the wireless terminal station newly joining investigates its own service area, If the central station does not exist, the own station becomes the central station, or confirms the presence from terminals belonging to at least two different sub-networks, and checks with any terminal belonging to all those sub-networks. If there is no communicable terminal, the local station becomes a relay station, or a subnet of a wireless terminal in which the central station exists and exists in the service area. If there is a relay station that recognizes all network IDs, or if there is a central station and all terminals in the service area have the same subnetwork ID, a subnetwork ID is also assigned. Has the effect that it is possible to clarify the role of its own terminal and to enter the network.

According to a fifth aspect of the present invention, when the central station turns off the power, the wireless terminal existing in the sub-network of the central station newly sets its own terminal as the central station or a slave station. 2. The wireless communication system according to claim 1, wherein when a wireless terminal serving as a central station leaves the system, the wireless terminal sends a leave notification to a subnetwork to which the own station belongs, and belongs to the subnetwork. The wireless terminal sequentially investigates its own service area, and can maintain the sub-network by resetting itself to the central station, relay station, or slave station, and maintain the connection between the sub-networks. It has the effect of being able to.

According to a sixth aspect of the present invention, when the relay station cuts off the power, it determines whether or not the relay station needs to be delivered, and if necessary, passes the relay station to another wireless terminal. 2. The wireless communication system according to claim 1, wherein the connection between the sub-networks is maintained, and when the wireless terminal serving as the relay station leaves the system, the sub-network ID recognized by the own station. If a substation that has all of the substations or one of the substations that has many substations is selected and the relay function can be transferred, the relay function transfer notification is sent, and the This has the effect of maintaining the connection and avoiding the complete isolation of the network.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment) FIG. 1 is a conceptual diagram showing a configuration example of a wireless communication network according to an embodiment of the present invention. In FIG. 1, 101 and 102 are sub-networks, 103 to 107 are wireless terminals,
And 104 are respectively subnetwork 101, 10
2 is the central station that determines 2. The radio terminal 107 is a radio wave from a radio terminal belonging to a different subnetwork, in this case, a radio terminal 103 belonging to the subnetwork 101.
Can receive both the radio wave from the sub-network 102 and the radio wave from the wireless terminal 104 belonging to the sub-network 102, and there is no other radio terminal that recognizes these two sub-networks. The relay station relays messages between the network 101 and the subnetwork 102. The wireless terminals 105 and 106 are within the communication range from the central stations 103 and 104, respectively, and serve as slave stations because there are no wireless terminals that can communicate directly and belong to different sub-networks.

Each wireless terminal stores its own station table as shown in FIG. 2 for storing information about its own station such as roles and belonging sub-networks, and a diagram for storing information such as its roles and belonging sub-networks for nearby terminals. 3 has a role table, and the role table includes a central station table, a relay station table, and a slave station table.

FIG. 4 shows a sequence diagram when a new radio terminal joins in the network configuration of FIG.
The new entry terminal broadcasts a new entry signal to its own service area. Each terminal receiving the new entry signal is shown in FIG.
The response processing shown in is performed. The subnetwork ID response signal transmitted to the new entry terminal by the response process is collected by the new entry terminal during the response period, and the information such as the subnetwork ID and role of each terminal is automatically recorded by the recording process shown in FIG. Recorded in the station management table. The newly joining terminal refers to this management table and determines its role according to the sub-network configuration processing shown in FIG. If the own station is the central station, it broadcasts a subnetwork configuration change packet. The central station that has received the role change packet corrects the change in its own station table as shown in FIG. 8, and transmits the subnetwork configuration change packet. The terminal that has received the subnetwork configuration change packet corrects the change in each role table as shown in FIG. 9, and the new network is completed.

The relay station and the slave station receiving the role change packet refer to the local station role table as shown in FIG. 10, and if there is a change, transfer the role update packet to the central station as necessary. Then, the central station notifies the change information to the wireless terminals in the sub-network and the role is determined.

Hereinafter, each of the processes shown in FIGS. 5 to 10 will be described using an example in which the role undetermined terminal 108 appears as shown in FIG.

FIG. 11 shows a flowchart of a response process when a new entry signal is received. The wireless terminal that has received the new entry signal includes all information in its own station table, that is, the terminal address of its own station (step 301), its belonging subnetwork ID (step 302), and The subnetwork ID of the wireless terminal belonging to another subnetwork existing in the service area of the station, that is, the owned subnetwork ID is stored (step 303). In the role indicator field, if the terminal is a relay station, the relay station indicator is stored (step 305), and if the terminal is a slave station, the slave station indicator is stored (step 307). Here, the terminal address is, for example, IEEE Std 802-1990.
Is uniquely determined by using the 48-bit address defined in the above, and the subnetwork ID is also uniquely determined by using the address of this terminal of the central station.

Each wireless terminal storing all the information elements,
The sub network ID response packet is sequentially transmitted to the newly joining station. In the case of FIG. 11, the wireless terminals 106 and 107 that have received the new entry signal from the wireless terminal 108 store the information in the local station table in the subnetwork ID response packet and sequentially transmit the information to the wireless terminal 108.

FIG. 6 shows a case where a new entry station is a subnetwork I
It is a flowchart which shows the process at the time of receiving a D response packet. If the terminal address in the response packet is equal to the belonging subnetwork ID, this is a response from the central station, so the terminal address is recorded in the central station table in the role table (step 402). The belonging subnetwork ID is recorded in the belonging subnetwork field (step 403).

If the responding terminal is a relay station, the terminal address, the belonging subnetwork ID and the owning subnetwork ID are recorded in the relay station table in the role table (step 405). If the belonging subnetworks are different, the belonging subnetwork ID is recorded in the owning subnetwork field of the own station table (step 409).

If the answering terminal is a slave station, the terminal address, the belonging subnetwork ID and the owning subnetwork ID are recorded in the slave station table in the role table (step 408). If the belonging subnetwork is different, the owning subnetwork ID is recorded in the belonging subnetwork field of the own station table (step 409).

FIG. 11 is a conceptual diagram showing an example of a new network configuration when a new wireless terminal 108 enters. In the case of FIG. 11, the newly entered wireless terminal 108 becomes the central station and forms a new sub-network 109, and the wireless terminal 1
The information of the packet from 06 is recorded in the slave station table and the information from the wireless terminal 107 is recorded in the relay station table.
Record the network IDs belonging to 6, 107.

FIG. 7 is a flowchart showing a process for determining the role of the own terminal based on the result recorded in the own terminal table. The process shown in FIG. 6 is performed during the response collection period. This is a process of determining the role of the own station based on the result. If there is no response from the central station, the terminal becomes the central station (step 50).
2) The own terminal address is added to the belonging subnetwork ID in the relay station field (step 503). It is determined whether or not the sub-network ID of the sub-station table is within the sub-network ID field of the relay station (step 504), that is, a new sub-network to which the sub-station belongs is set, and the network is connected. If necessary, all the information in the corresponding slave station field is transferred to the relay station field (step 505), and the subnetwork configuration change packet is broadcast.

Also, if there is a response from the central station, and if the subnetwork ID of the substation does not exist in any of the substation IDs belonging to the relay station and the slave station table in the role table, or if the subnetwork ID does not exist in any of the subnetwork ID fields, The own subnetwork ID of the own terminal is additionally recorded in the own subnetwork field of the table and the slave station table (step 507). With reference to the relay station table, it is determined whether or not there is a relay station having the belonging subnetwork ID of all responding stations, that is, the belonging and owned subnetwork ID in the own station table (step 50).
8) If it exists, the own terminal becomes a slave station (step 5).
12) If not, it becomes a relay station (step 50)
9).

After the terminal is determined to be the relay station, if the combination of the subnetwork IDs of the respective wireless terminals in the slave station table does not exist in the relay station table, the slave station field is shifted to the relay station field (step 511) The role change packet is transmitted to the central station and the terminal whose role has been changed. In the case of FIG. 11, since there is no response from the central station, the own terminal is determined to be the central station, and the own terminal address is recorded in the belonging subnetwork field of the own station table. Since it exists in the table, the role transfer process is not performed, and the information of the own station table and the role table of the own terminal is stored and transmitted in the subnetwork configuration change packet.

FIG. 10 is a flowchart showing a change process when a role change packet is received. The terminal that has received the role change packet corrects the change if there is a change in the own station table and the role table (step 602). If the source of the change packet is not the subnetwork belonging to the own terminal, the terminal changes the role. The self-station table information and the role indicator after the correction are stored in the packet and transmitted to the sub-station central station belonging to the self-terminal (step 604). If the own terminal is the central station, if there is any change in each role table, it is corrected (step 607), and all information relating to the own terminal's own role table is stored in the subnetwork configuration change packet and broadcast. Yes (Step 60
8).

FIG. 8 is a flowchart showing the processing of the central station when the role change packet is received. When the central station receives the role change packet, the change is corrected for each role table (step 701). All information relating to the role table owned by the terminal itself is stored in the subnetwork configuration change packet and is broadcasted (step 70).
2).

FIG. 9 is a flowchart showing the processing of the wireless terminal that has received the subnetwork configuration change packet. The terminal that has received the subnetwork configuration change packet corrects the changes in each role table (step 8).
01), the new network configuration is completed. In the case of FIG. 11, the wireless terminals 106 and 107 record the belonging subnetwork ID of the wireless terminal 108 in the belonging subnetwork field in the own station table.

The above processing is performed, and even if there is a new entry terminal, it is possible to obtain
The roles of the central station, relay station, and slave station can be easily assigned.

FIG. 12 shows a sequence in a case where an arbitrary terminal constituting the network leaves the network. A wireless terminal that is about to leave the network first performs a leaving process shown in FIG.

As shown in FIG. 13, in the leaving process, it is determined whether or not the own station is a relay station (step 1101).
If it is not a relay station, it directly broadcasts the leaving packet (step 1104). If it is a relay station, it is determined whether or not there is a wireless terminal that recognizes both the belonging / owned sub-network ID of its own terminal (step 1102). The child is stored in the leaving packet (step 1103), and the leaving packet is broadcasted (1104).

The wireless terminal that has received the leaving packet is shown in FIG.
Perform the role change / table update process shown in FIG. First, the role of the source of the leaving packet is identified (step 120).
1, step 1207), if it is the central station, the corresponding subnetwork ID is deleted from the belonging subnetwork field of the own station table (step 1202). If only one subnetwork ID exists in the subnetwork field of the own station, the role indicator of the own terminal is set as the slave station (step 1206), and a role update packet is transmitted to the center station of the own subnetwork. If there is no subnetwork ID in the belonging subnetwork field, the new entry process is performed (step 1).
204).

If the source of the leaving packet is a relay station, it is determined whether or not the relay function is to be transferred to the own terminal (step 1208). If the relay function is to be transferred to the own terminal, the role indicator of the own terminal is set. As a relay station (step 1209), a role update packet is transmitted to the central station to which the subnetwork belongs. If the own terminal is a relay station (step 1210),
It is determined whether or not a plurality of subnetwork IDs are recognized due to the detachment of the source wireless terminal (step 1211),
When recognizing only the network belonging to the own terminal, the role indicator is set to the slave station, and the role packet is transmitted.

By following the above procedure and receiving the role update packet, the central station broadcasts the subnetwork configuration change packet, thereby completing the network reconfiguration after a wireless terminal leaves the network. In addition, the maintenance of the sub-networks and the connection between the sub-networks can be maintained, and the complete separation of the networks can be avoided.

[0038]

As described above, according to the present invention, a central station for determining a sub-network can be determined for a wireless network, and a relay station can be easily selected from the attributes of the sub-network. Even if a wireless terminal is introduced, expansion of the subnetwork can be realized by an appropriate procedure, and it is not necessary to install fixed stations or specific base stations previously installed, and it is possible to easily expand the network only with wireless terminals The advantageous effect that it can be obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration example of a wireless communication network according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an internal configuration of a local station table according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram showing the internal configuration of various tables in a role table according to an embodiment of the present invention. (A) Internal configuration diagram of a central station table (b) Internal configuration diagram of a relay station table (c) Child station table Internal configuration diagram

FIG. 4 is a sequence diagram when a wireless terminal newly enters in the embodiment of the present invention;

FIG. 5 is a flowchart of a response process when a new entry signal is received in the embodiment of the present invention.

FIG. 6 is a flowchart showing processing when a new entrant station receives a subnetwork ID response packet in the embodiment of the present invention.

FIG. 7 is a flowchart showing a process of determining the role of the own terminal based on the result recorded in the own terminal table in the embodiment of the present invention.

FIG. 8 is a flowchart showing processing of the central station when a role change packet is received in the embodiment of the present invention.

FIG. 9 is a flowchart illustrating processing of a wireless terminal that has received a subnetwork configuration change packet in the embodiment of the present invention.

FIG. 10 is a flowchart showing a change process when a role change packet is received in the embodiment of the present invention.

FIG. 11 is a conceptual diagram showing an example of a new network configuration when a new wireless terminal has joined in the embodiment of the present invention.

FIG. 12 is a sequence diagram when an arbitrary terminal configuring the network leaves the network according to the embodiment of the present invention;

FIG. 13 is a flowchart of a leaving process of a wireless terminal leaving the network in the embodiment of the present invention.

FIG. 14 is a flowchart of a role change process when a leaving packet is received in the embodiment of the present invention.

[Explanation of symbols]

 101, 102 Sub-network 103, 104 Wireless terminal (center station) 105, 106 Wireless terminal (relay station) 107 Wireless terminal (slave station) 108 New entrant wireless terminal 109 New sub-network

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K033 AA09 BA04 CB01 CB08 DA02 DA05 DA17 DB12 DB18 EA07 EC03 5K067 AA22 BB21 DD11 DD17 DD19 DD24 EE02 EE06 EE16 EE25 FF02 HH23 KK05 KK15

Claims (6)

[Claims] In a wireless network composed of a plurality of wireless terminals, a central station which is a wireless terminal forming a subnetwork having a clear boundary, a relay station which is a wireless terminal connecting the plurality of subnetworks, And a slave station that is neither of these and belongs to at least one subnetwork. 2. The wireless communication according to claim 1, wherein when any wireless terminal detects that the central station is not present in the service area of the own terminal, the wireless terminal sets the own terminal as the central station. system. 3. The wireless communication system according to claim 1, wherein when an arbitrary wireless terminal detects that the own terminal belongs to a plurality of sub-networks, the own terminal is set as a relay station. . 4. When a new wireless terminal joins a wireless network, the new wireless terminal searches in a service area of the own terminal, and based on a search result, sends the new wireless terminal to one of a central station, a relay station, and a slave station. The wireless communication system according to claim 1, wherein a new wireless terminal is set. 5. The wireless communication system according to claim 1, wherein when the central station turns off the power, the wireless terminal existing in the sub-network of the central station newly sets its own terminal as the central station or a slave station. Wireless communication system. 6. When the relay station turns off the power, it determines whether or not the relay station needs to be handed over, and if necessary, transfers the relay station to another wireless terminal to maintain the connection between the sub-networks. The wireless communication system according to claim 1, wherein: