JPH11163875A - Radio lan system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio LAN system by which a radio terminal can easily obtain its own position without increasing the processing amount of its own and the entire system. SOLUTION: A radio LAN system 1 is built by including a radio terminal 10 that makes radio communication between communicable bridges; a plurality of bridges (radio base stations) with predetermined positioning 20a, 20b,... connected via a wire network W1; and a terminal position information management server 30 that acquires a relative position of the radio terminal 10 from each bridge through the wired network W1 and informs each bridge of the acquired relative position of all the radio terminals 10. The bridges 20a, 20b... provide multiaddress information of the relative positions received from the terminal position information management server 30 to all the radio terminals 10 and the radio terminals 10 specify its own current position based on the received relative positions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network technology to which mobile computing technology is applied, and in particular, a portable terminal having a wireless communication function (hereinafter, wireless terminal) freely moves within a predetermined area. Sometimes a wireless LAN that allows a wireless terminal to detect its current location
The present invention relates to a system and its constituent devices.

[0002]

2. Description of the Related Art A wireless LAN system has been put into practical use for performing information communication between wireless terminals or between a wireless terminal and a computer device connected to a wired network using radio waves as a transmission medium. In Japan, the transmission frequency is 2.4
Using a band of GHz or 19 GHz, the transmission speed is several bps to several tens of Mbps, and the reach distance to the wireless terminal is several tens of meters.
A wireless LAN system having the performance described above has been put to practical use. Regarding the basic technology of this wireless LAN system,
"Mobile Communication Handbook" [Co-edited by Sato and Tachikawa: Ohmsha (1995)] and "Introduction to Wireless Data Communication" [Research Group for Wireless Data Communication: Soft Research Center (199)
4)].

FIG. 6 is a diagram showing a general configuration example of a wireless LAN system. This wireless LAN system 60
Are wireless terminal 61, wireless terminal 61 and wired network W
And a plurality of bridges (wireless base stations) 62, 63, and 64 for interconnecting with each other. Bridge 6
2-64 are respectively located at geographically separated positions,
Wireless communication can be performed over a wide area with the wireless terminal 61 moving in the area covered by the cells C1, C2, and C3.

[0004] When the radio terminal 61 moves from one cell to another cell, a process of changing a bridge to be a communication partner is required. This process is called roaming (or handover). As a wireless LAN system having the roaming function, for example, there is "Wave LAN" by NCR Japan [Wave LAN WavePOINT Manual: NCR Japan, and Local Area Networks, BYTE,
June 1995 (see Baldazo et al.)]. Such a wireless LAN
In the system, each bridge holds a list of identifiers of wireless terminals that are currently communicating, that is, a terminal management list. As the identifier, for example, a hardware address (such as a MAC address in Ethernet) of the network interface of the wireless terminal is used.

[0005] For example, in FIG. 6, consider that the radio terminal 61 moves from the cell C1 to the cell C2. Cell C1
, The wireless terminal 61 is in wireless communication with the bridge 62, and the identifier of the wireless terminal 61 is described in the terminal management list of the bridge 62. When the wireless terminal 61 moves from the cell C1 to the cell C2 in this state, the cell C1
Since communication with the terminal becomes difficult, the wireless terminal 61 changes the communication partner from the bridge 62 to the bridge 63 at a certain timing. As a result, the identifier of the wireless terminal 61 is deleted from the terminal management list of the bridge 62, and is newly registered in the terminal management list of the bridge 63. Since the roaming function is performed by the wireless LAN driver on the wireless terminal 61 and the software on each bridge, the application program in the system and the user of the wireless terminal 61 need to recognize that roaming is being performed at all. Absent.

[0006]

Incidentally, as an application form of the wireless LAN system in an environment where the user moves together with the wireless terminal, there is an information providing service for providing information according to the current position of the wireless terminal. For example, a visitor (user) has a wireless terminal in a museum or a museum, and bridges are arranged at various places in the building so that the wireless terminal can access the network in the building. Then, when the visitor stops at each exhibition, information on the exhibit is acquired from the network and presented to the visitor, so that necessary information can be appropriately provided according to the position.

[0007] In order to realize such an information providing service, the application program on the wireless terminal needs to always recognize the position information on the current position of the application program. Since the bridge has a terminal management list for wireless terminals that exist in the cell, if it can be confirmed that the wireless terminal exists in its own cell, it obtains necessary information via the wired network and This can be provided to the wireless terminal.

However, in order for the wireless terminal to know its own current position, it is necessary to access all the bridges in order, search the terminal management list, and check whether its own identifier is registered. Become. In addition, since the wireless terminal has to repeat this process at least at regular intervals and maintain the position information, there is also a problem that the amount of processing to be executed by the wireless terminal becomes very large. Even from the viewpoint of the entire system, the amount of information flowing on the network becomes extremely large.

An object of the present invention is to provide an improved wireless LAN system for efficiently acquiring position information of a wireless terminal, and an apparatus therefor.

[0010]

A wireless LAN system according to the present invention for solving the above-mentioned problems is obtained from each wireless base station,
A terminal position information management device that notifies each of the obtained relative position information of the wireless terminals to each of the wireless base stations, wherein the plurality of wireless base stations are respectively notified of the relative position notified from the terminal position information management device. The wireless terminal has means for broadcasting information to all the wireless terminals, and the wireless terminal has means for specifying its own current position based on the received relative position information.

According to another wireless LAN system of the present invention, monitoring information indicating the presence or absence of the plurality of wireless base stations and wireless terminals and the wireless terminal whose communication partner wireless base station has been changed is transmitted to each wireless base station through the network. From the base station,
A terminal position information management device that notifies each wireless base station of the identification information of the wireless terminal and at least the changed wireless base station each time the wireless base station detects the changed wireless terminal based on the acquired monitoring information. Comprising, the plurality of wireless base stations each have means for broadcasting the identification information notified from the terminal location information management device to all of the wireless terminals, wherein the wireless terminal receives It is characterized in that it has means for specifying its own current position based on the identification information.

The terminal location information management device simultaneously obtains information from each radio base station and performs the notification by broadcasting. Alternatively, the information acquisition from each wireless base station is performed simultaneously and periodically, and when there is a difference from the previously obtained information, the information of the difference is continuously and repeatedly broadcast to notify each wireless base station, When there is no difference, the obtained information is repeatedly broadcasted at predetermined intervals and notified to each radio base station.

[0013] The plurality of radio base stations may be classified into a plurality of groups, and the terminal location information management device may exist for each group.

The present invention also provides a constituent device of the wireless LAN system, that is, a terminal position information management device. In this terminal position information management device, the arrangement position is determined in advance,
Connecting to the wired network in a wireless LAN system including a plurality of wireless base stations connected via a wired network and a wireless terminal performing wireless communication with a communicable wireless base station The first means for acquiring identification information and the location information of each communicable wireless terminal from each wireless base station through the wired network, and the acquired identification information of all the wireless terminals and Second means for broadcasting the location information to all the wireless terminals, wherein each of the wireless terminals is configured to specify its own current location through the broadcasted identification information and the location information. Features.

Another terminal position information management device according to the present invention is a third means for acquiring, from each wireless base station, monitoring information indicating the presence or absence of the wireless terminal whose communication partner wireless base station has been changed, through the network. And, every time the wireless base station detects the changed wireless terminal based on the acquired monitoring information, broadcast the identification information of the wireless terminal and at least the changed wireless base station to all the wireless terminals. And four wireless terminals, wherein each of the wireless terminals specifies their own current position through the broadcasted identification information.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of a wireless LAN system according to an embodiment of the present invention. The wireless LAN system 1 includes a plurality of bridges (wireless base stations) 20a, 20b,.
. And one terminal location information management server 30, and the wireless terminals 10 in the cells C1, C2,... Of each bridge 20a, 20b,. Each bridge 20
a, 20b,... and the wireless terminal 10 or the wireless terminal 1
A wireless LAN is formed between the 0s.

The wireless terminal 10 includes bridges 20a, 20
b,... and a wireless LAN interface unit that constantly monitors the status of the wireless communication of the wireless LAN interface unit, and a terminal position described later based on information received through the wireless LAN interface unit 11. Location information acquisition unit 12 for acquiring information, location information storage unit 1 for storing acquired terminal location information in an updatable manner
3. It has an AP (application) processing unit 14 that performs various processes based on the stored terminal location information.

These functional blocks are formed by a computer device, for example, a notebook personal computer or a PDA (Personal Digital Assistant) terminal reading and executing a predetermined program. This wireless terminal 10 has bridges 20a, 20
.. can move freely among a plurality of cells C1, C2,... while communicating with a computer connected to the wired network W1 via b,. .

The wired network W1 supports a broadcast function of simultaneously transmitting the same information in one transmission to all the wireless terminals with which each bridge can communicate through the bridges 20a, 20b,. ing. That is, when the wired network W1 uses the IP protocol on the Ethernet, the IP broadcast function defined by the IP protocol can be used. The broadcast function itself is known.

The bridge 20a includes a bridge processing unit 21 for performing communication control processing with the wireless terminal 10 existing in its own cell and the terminal location information management server 30 connected via the wired network W1, A terminal information management unit 22 that performs terminal management processing necessary for realizing roaming, and a list storage unit 23 that stores a terminal management list created by the terminal information management unit 22 and referred to as needed. The bridge processing unit 21 also has a function of broadcasting information from the terminal location information management server 30 to all communicable wireless terminals.

The terminal management list contains the communicable wireless terminals 1
It is a list of identification information of 0 and other management information. That is, when the wireless terminal 10 enters its own cell, information about the wireless terminal 10 is recorded. On the other hand, when the wireless terminal 10 moves to a cell of another bridge, all information about the wireless terminal 10 is recorded. Is deleted. Therefore, on the terminal location information management server 30 side, this terminal management list can be used as monitoring information indicating the presence or absence of a wireless terminal whose communication partner bridge has been changed.

These functional blocks are formed by a computer device that implements a bridge reads and executes a predetermined program. Other bridge 20
are similarly configured.

The terminal location information management server 30 has a network interface unit 31 for providing an interface for wired communication with the wired network W1, and accesses the bridges 20a, 20b,... Periodically through the network interface unit 31. Access unit 3 to read terminal management list held by each bridge
2. A terminal position information storage unit 33 that integrates all the read terminal management lists and stores terminal position information indicating in which cell each wireless terminal 10 is currently located in a wireless terminal unit so as to be freely updated. Compare the obtained terminal location information and the currently held terminal location information, and determine whether there is a wireless terminal whose cell position has been changed,
If there is a wireless terminal whose cell position has been changed, a difference information extracting unit 34 for extracting change information (difference information) for the wireless terminal, and information or difference information in the terminal position information storage unit 33 are broadcast on the network. A broadcast unit 35 is provided for selectively performing simultaneous broadcast to all wireless terminals by using the function. The functional blocks 31 to 35 are also formed by a computer having a server function reading and executing a predetermined program.

The broadcast unit 35 can change the cycle of the broadcast and the number of repetitions of the same information depending on whether the information to be transmitted is the difference information or the terminal location information which is not updated even after a certain period of time. . For example, in the case of the difference information, although the data size at one time is small, the radio terminal 10 may fail to receive the data, so this is continuously and repeatedly broadcast several times. On the other hand, if the terminal location information is not updated,
The broadcast is repeated intermittently about two or three times.

As shown in FIG. 2, the terminal location information includes, for example, a terminal identifier (hardware address) for uniquely identifying the radio terminal 10 and a cell of a bridge in which the radio terminal 10 exists. And a set of cell identifiers. The cell and the bridge are associated with each other in advance, and the installation position of the bridge is predetermined, so that by decoding the terminal position information, the current position of the wireless terminal 10 can be specified. That is, the terminal position information is information indicating the relative position of the wireless terminal 10. Note that the terminal location information only needs to be able to specify the location of the wireless terminal 10, and thus, instead of the cell identifier, the identification information of the bridge before and after the cell change, particularly, the bridge after the change can be used.

In the wireless LAN system 1 configured as described above, a procedure until the wireless terminal 10 actually specifies its current position will be described with reference to FIGS. FIG. 3 shows a processing procedure in the bridges 20a, 20b,. The bridges 20a, 20b,... Normally relay the contents of wireless communication performed between the wired network W1 and the wireless terminal 10, but the wireless terminal 10 may be away from its own cell range, That the cell has moved from its own cell to its own cell range.
, The wireless terminal 10 moves and recognizes that the bridge serving as the communication partner has been changed (step S101),
The content of the terminal management list in the list storage unit 23 is updated (Step S102).

The movement of the wireless terminal 10 can be detected by a connection request issued from the wireless terminal 10 to the bridge when the wireless terminal 10 newly moves into the cell range. On the other hand, when the wireless terminal 10 moves out of the cell range and moves to a cell of another bridge, the wireless terminal 10 similarly issues a connection request to the bridge of the movement destination. Then, the connection to the new wireless terminal 10 is notified to the other bridges, so that the connection can be detected.

FIG. 4 shows a processing procedure in the terminal location information management server 30. Terminal location information management server 3
0, the bridge access unit 32 is connected to the wired network W
1, all bridges 20a, 20b,
, And reads out the terminal management list held in each bridge (step S201). At this time,
It is desirable to access a plurality of bridges simultaneously and read the terminal management list in parallel. This makes it possible to further speed up the process of reading the terminal management list. Access to each bridge is, for example, SNM
P (Simple Network Management Protocol, RFC1157.)
This can be realized by following.

When the terminal management list has been read from all the bridges (step S202), the difference information extracting unit 34 then obtains the terminal position information acquired this time and the terminal position information already stored in the terminal position information storage unit 33. And compare
If there is a change, difference information is created (step S20).
3). Further, the content of the terminal location information storage unit 33 is updated to the content of the terminal location information acquired this time (step S20).
4). Thereafter, the broadcast unit 35 broadcasts the difference information or the information in the terminal location information storage unit 33 to all wireless terminals (step S205).

FIG. 5 shows a processing procedure in the wireless terminal 10. In the wireless terminal 10, the wireless LAN interface unit 11 constantly monitors the wireless communication status and waits for the difference information or the terminal location information to be broadcast from the bridges 20a, 20b,... (Step S30).
1: No). When the difference information or the like is received (step S3
01: Yes), this is notified to the position information acquisition unit 12.
The position information acquisition unit 12 analyzes the received information and confirms whether there is difference information or the like in which the own terminal identifier is described. If there is information describing the own terminal identifier (step S302: Yes), the cell identifier or the identification information of the bridge before and after the change is extracted, and the terminal position information is updated (step S303). This allows
The AP processing unit 14 can easily specify in which cell the self currently exists. After the location is specified, the location is transmitted to the information server connected to the network through the bridges 20a, 20b,..., So that, for example, service information corresponding to the location can be obtained through the network.

As described above, in the wireless LAN system 1 of the present embodiment, the terminal location information management server 30
0a, 20b,..., And obtains terminal position information of all communicable wireless terminals 10 and broadcasts the obtained terminal position information to each wireless terminal. As described above, it is not necessary for the wireless terminal and the bridge to individually detect the terminal positions, and the processing amount in each terminal and the increase in the data amount on the wireless LAN or the wired network W1 are suppressed.

Also, since the terminal location information is broadcast to all the wireless terminals simultaneously by the broadcast function supported by the network, the terminal location information is transmitted at a higher speed as compared with the case of notifying each wireless terminal one-to-one. become able to.

In this embodiment, a plurality of bridges 2
0a, 20b,..., One terminal location information management server 30 is provided.
a, 20b,... may be divided into several groups, and a terminal location information management server having the above-described configuration may be provided for each group to distribute server processing. In this way, the processing of each terminal location information management server is reduced, and the wireless terminal 10 can more quickly acquire the terminal location information.

The wireless terminal 10 may be configured to hold not only its own terminal position information but also other terminal position information. This makes it possible to realize an information service in which, for example, wireless terminals at close distances communicate with each other.

[0035]

As is apparent from the above description, according to the present invention, the terminal location information for all the radio terminals is notified from the terminal location information management device to each radio terminal through the radio base station. This has the effect of reducing the amount of processing on a wireless terminal or a wireless base station, and the amount of data on a wireless LAN or a wired network as compared with the prior art.

Further, since the terminal location information is repeatedly and simultaneously notified to each wireless terminal by broadcast, the information can be transmitted at high speed and reliably. Furthermore, when notifying the terminal location information to each wireless terminal, by notifying only information about the wireless terminal that has changed compared to the previous time, the data amount of one notification can be further reduced. .

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a wireless LAN system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of terminal position information used in the present embodiment.

FIG. 3 is an explanatory diagram of a processing procedure in a bridge (wireless base station).

FIG. 4 is an explanatory diagram of a processing procedure in the terminal location information management server.

FIG. 5 is an explanatory diagram of a processing procedure in the wireless terminal.

FIG. 6 is an explanatory diagram of a conventional example of a wireless LAN network system.

[Explanation of symbols]

 Reference Signs List 1 wireless LAN system 10 wireless terminal 11 wireless LAN interface unit 12 position information acquisition unit 13 position information storage unit 14 AP (application) processing unit 20a, 20b bridge (wireless base station) 21 bridge processing unit 22 terminal information management unit 23 list storage Unit 30 terminal location information management server 31 network interface unit 32 bridge access unit 33 terminal location information storage unit 34 difference information extraction unit 35 broadcast unit C1, C2 cell W1 wired network

Claims (8)

[Claims] A wireless terminal that performs wireless communication between a plurality of wireless base stations, each of which has an arrangement position determined in advance and is connected via a wired network, and a communicable wireless base station. A terminal position information management device that obtains the relative position of each wireless terminal from each wireless base station through the wired network, and notifies each wireless base station of the relative positions of all the obtained wireless terminals. The base station has means for broadcasting the relative position notified from the terminal position information management device to all of the wireless terminals, and the wireless terminal has its own current position based on the received relative position. A wireless LAN system having means for specifying a position. 2. A wireless terminal for performing wireless communication between a plurality of wireless base stations, each of which has an arrangement position determined in advance and each connected via a wired network, a communicable wireless base station, and a communication partner. The wireless base station obtains monitoring information indicating the presence or absence of the changed wireless terminal from each wireless base station through the network, and detects the changed wireless terminal based on the obtained monitoring information. Terminal position information management device that notifies each wireless base station of the identification information of the wireless terminal and at least the changed wireless base station at each time, wherein the plurality of wireless base stations are respectively from the terminal position information management device. Means for broadcasting the notified identification information to all of the wireless terminals, wherein the wireless terminal specifies its own current position based on the received identification information. Wireless LAN system, characterized by. 3. The wireless LAN system according to claim 1, wherein the terminal location information management device simultaneously obtains information from each wireless base station, and performs the notification by broadcasting. 4. The terminal location information management device simultaneously and periodically acquires information from each radio base station, and when there is a difference from the last acquired information, continuously broadcasts the information of the difference by broadcasting. 3. The wireless communication system according to claim 1, wherein said wireless base station is repeatedly notified at a predetermined interval by broadcast when the difference does not exist.
AN system. 5. The radio according to claim 1, wherein the plurality of radio base stations are classified into a plurality of groups, and the terminal location information management device exists for each group. LAN system. 6. A plurality of radio base stations, each of which has a predetermined installation position and is connected via a wired network,
An apparatus connected to the wired network in a wireless LAN system including a wireless terminal performing wireless communication with a communicable wireless base station, wherein identification information of each communicable wireless terminal is provided. And first means for acquiring the location information from each wireless base station through the wired network, and second means for broadcasting the acquired identification information of all the wireless terminals and the location information to all the wireless terminals. A terminal location information management device, characterized in that the terminal location information management device is configured to cause each wireless terminal to identify its own current location through the broadcasted identification information and its location information. 7. A plurality of wireless base stations, each of which has an installation position determined in advance and is connected via a wired network,
A device connected to the wired network in a wireless LAN system including a wireless terminal performing wireless communication with a communicable wireless base station, wherein a wireless base station to be communicated with is changed. Third means for acquiring the monitored information indicating the presence / absence of the wireless terminal from each wireless base station through the network; and each time the wireless base station detects the changed wireless terminal based on the acquired monitoring information, Fourth means for broadcasting the identification information of the wireless terminal and at least the changed wireless base station to all of the wireless terminals, and causing each wireless terminal to specify its own current position through the broadcasted identification information. Terminal position information management device characterized by being configured as described above. 8. The terminal location information management device according to claim 6, wherein the broadcast is repeated a plurality of times with the same content.