JP2003333054A - Wireless local area network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conduct comfortable wireless communication with a maximum performance in a wireless local area network system in which a wireless client terminal connected by radio upon use of an access point does not receive interferences from radio waves. <P>SOLUTION: In a wireless local area network system, where a plurality of client terminals 4 having a wireless communication function, and at least one access point 1 having a wireless communication function and a wired local area network function, and managing the client terminals 4 are connected by radio, and the access point 1 is connected to a trunk network system by a wired local area network 2, the access point 1 has a function of transmitting a specific packet, in order to confirm an existence of another access point 1 around the access point 1 by the wireless communication. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless local area network (LAN) system in which a plurality of client PCs (terminals) are wirelessly connected.

[0002]

2. Description of the Related Art There are the following techniques for increasing the communication speed of a wireless LAN as much as possible. JP-A-9-2
In Japanese Patent No. 00211, the wirelessly connected slave station determines the transmission path. Alternatively, it is proposed to install a memory and delete the disconnected slave station from the registration.

Japanese Patent Laid-Open No. 11-175437 proposes a technique in which a buffer for absorbing a difference in speed between interfaces is provided and a host computer controls communication according to the state of the buffer.

[0004]

[Problems to be Solved by the Invention] Wireless LA until a few years ago
The N system was expensive, and the equipment was large-scale and difficult to obtain. Also, in terms of communication speed (performance), the performance is not satisfactory for a wireless system used for small-scale office use, even if it is a large-scale wireless system.

However, in recent years, the cost has become low, and the form provided by each wireless system manufacturer is a PC.
An MCIA card-sized wireless LAN device has been released, is very easy to obtain, and is beginning to spread to the market.

The 2.4 GHz band (also referred to as ISM band) used for wireless LAN is a frequency band that can be used without permission from a public institution, and due to technical improvements, the communication speed (performance) can be up to 11 Mbps. The improvement also seems to be adding to the expansion of the market.

The wireless LAN is a peer-to-peer system (Adhoc) for connecting two client terminals to each other.
Mode) and a wireless LAN access point to connect a plurality of client terminals to each other, and a core wired LAN.
Method that can be connected with (infrastructure mode method)
Has been put to practical use.

The communication distance is 50 m indoors and 100 m outdoors
Degree is general. The transfer speed (performance) is 11 Mbps that conforms to the IEEE 802.11b standard, which is an international standard for wireless LAN, and is comparable to the existing wired LAN, 10Base-T (10 Mbps), and is in the market. It has become a factor in the spread.

However, the frequency band used by the wireless LAN is the 2.4 GHz band, which is also called the ISM band, and there are many devices using this frequency band in the market. Therefore, the communication speed often decreases due to radio wave interference.

Even when using an access point, it is recommended that the number of client PCs to be wirelessly connected be about 10, and if the number of connected client PCs is more than this, communication performance will be significantly reduced due to radio wave interference. Communication may be interrupted depending on the usage environment.

As an idea for maximizing the communication speed (performance) of a wireless LAN, a device for centrally controlling wireless communication is provided to constantly monitor the state of each wirelessly connected slave station. A plan to try to maximize the performance by providing a buffer to absorb the difference in the transfer speed between the connected slave stations and a plan to try to transfer the data at the maximum transfer speed that can be transferred have been published. There is.

It is an object of the present invention to allow a wireless client terminal wirelessly connected when an access point is used in a wireless local area network system to perform comfortable wireless communication with maximum performance without receiving radio wave interference. .

[0013]

In order to achieve the above object, the invention according to claim 1 has a plurality of client terminals having a wireless communication function, and a wireless communication function and a wired local area network function. At least one access point that manages the client terminal is wirelessly connected, and the access point is connected to a core network system by a wired local area network. In the wireless local area network system, the access point is wirelessly communicated. A wireless local area network system having a function of transmitting a unique packet for confirming the existence of other access points existing around the access point is the most main feature.

According to a second aspect of the present invention, in the wireless local area network system according to the first aspect, when it is determined that the access point can communicate with other access points in the vicinity, the access point is set to the other access point with which communication is possible. The main feature is a wireless local area network system that has a function of acquiring channel information.

According to a third aspect of the present invention, in the wireless local area network system according to the second aspect, an unused channel is searched for based on the set channel information of each of the other access points existing around the access point. The main feature is a wireless local area network system having a function of automatically setting a channel.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of a network system in which a wireless local area network system and a wired local area network system are mixed.

Reference numeral 1 (1-1, 1-2) indicates an access point (AP), and in this example, the AP 1-2 is connected to the wired local area net 2. Of course, it is possible that two or more AP1s are connected. Also, each AP 1 does not necessarily have to be a wired local area network 2
Is not connected to.

In the wireless local area network 3-1 of AP1-1, six client terminals 4 are connected to AP1-
Five client terminals 4 are wirelessly connected to the wireless local area network 3-2.
AP1-1 and AP1-2 exchange information with each other by wireless communication. The content of the information is an IP address set in each AP 1, communication setting information, status information, and the like.

The client terminal 4 belonging to each wireless local area network 3 is set with the ID set in the AP 1 of the wireless local area network 3, and the client terminals 4 in the wireless local area network 3 communicate with each other. Communication is not possible unless this ID is the same.

FIG. 2 shows an example of exchanges when the two APs shown in FIG. 1 perform wireless communication. AP1-
Before AP 1 starts communication operation, AP1 (AP1
In order to investigate -2), a unique packet for AP search is transmitted. Other AP1 that received this packet
(AP1-2) returns an Ack signal (packet) for responding to the packet.

When the AP1-1 detecting the returned Ack signal, the request signal for the communication setting information and the like held by the AP (AP1-2) that issued the Ack is detected. Give out. (AP1-2) transmits desired data in response to the request signal.

FIG. 3 is a flow chart of the control operation of the present invention. When the power of a certain AP is turned on or the communication operation is to be started by another action, first, a packet for searching for an AP existing in the vicinity of the AP is transmitted (S1). After waiting for an Ack signal from another AP (S
2) When an Ack signal from any AP is received (S3), the AP that transmitted the Ack signal is specified (S3).
4), communication setting information is acquired from the AP (S5).
If no Ack signal is returned, it is determined that there are no APs using the same channel in the vicinity, and normal communication operation starts with the channel setting state set by default.

An unused channel is searched from the acquired communication setting information (S6), and when it is determined that an unused channel exists (Y in S7), the unused channel is set. If there are multiple unused channels, select a channel whose frequency domain is sufficiently far from the used channel. If there are no unused channels (S
7, N), and sets the channel that is used less frequently among the used channels (S9). After that, the normal communication state is entered.

[0024]

As described above, according to the present invention,
When the AP determines that the AP can communicate with other APs existing in the vicinity by transmitting a peculiar packet for confirming the existence of other APs existing in the vicinity of the AP by wireless communication, It is possible to acquire channel information set in other APs with which communication is possible. Therefore, it is possible to search for an unused channel based on the setting channel information of each of the other APs existing around the AP and automatically set the channel, which is caused by using the same channel. The influence of radio wave interference and the like is eliminated, and the performance of wireless communication in the local area network created by each AP can be maintained.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a network system in which a wireless local area network system and a wired local area network system are mixed.

FIG. 2 is a diagram showing an example of exchanges when the two APs shown in FIG. 1 perform wireless communication.

FIG. 3 is a flowchart of a control operation of the present invention.

[Explanation of symbols]

1 access point 2 Wired local area network 3 wireless local area network 4 client terminals

Claims (3)

[Claims] 1. A plurality of client terminals having a wireless communication function, and at least one access point for managing the client terminals having a wireless communication function and a wired local area network function are wirelessly connected to each other, and access is made. A point is connected to a backbone network system by a wired local area network. In a wireless local area network system, an access point is used to confirm the existence of other access points in the vicinity of the access point by wireless communication. A wireless local area network system characterized by having a function of transmitting a unique packet. 2. The wireless local area network system according to claim 1, wherein when it is determined that the access point can communicate with other access points existing in the vicinity, channel information set in the other access points with which communication is possible is performed. A wireless local area network system having a function of acquiring. 3. The wireless local area network system according to claim 2, wherein an unused channel is searched for automatically based on the set channel information of each of the other access points existing in the vicinity of the access point. A wireless local area network system having a function of setting a channel.