JP2007036381A - Telephone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a telephone system with the quality enhanced, by improving data loss when an access point is switched. <P>SOLUTION: When an authenticated wireless LAN terminal 10 moves from the area of a wireless LAN access point 20 inside the area of a wireless LAN access point 30, authentication is performed again for the wireless LAN access point 30 in the moving end area. The wireless LAN terminal 10 transmits authentication result information, additionally, as information indicating that it has been authenticated for a wireless LAN system. When registration of data received from an authentication information management server 100 on a database managed by itself and transmitted authentication result information can be checked, the wireless LAN access point 30 permits reconnection, while a part of transmission/reception procedure is omitted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an improvement of a telephone system that transmits an audio signal in a wireless LAN network.

In recent years, a system for realizing telephone communication using a best effort type communication network such as the Internet instead of the conventional telephone line has been realized. This kind of system is called VoIP (
Also referred to as Voice over Internet Protocol. VoI
P has advantages such as realization cost and expandability, but quality cannot be guaranteed unlike a widely used bandwidth guarantee type telephone wired network. In VoIP, quality deterioration occurs due to packet loss, delay, instantaneous interruption, jitter, and the like, and an improvement technique has been proposed. For example, a packet loss compensation unit that holds past voice packets in a buffer and guarantees a silent part by combining repetition and attenuation has been standardized (for example, see Non-Patent Document 1).

Recently, a wireless IP telephone that combines the VoIP and a wireless LAN network that performs wireless communication with a conventional wired network as a communication network has attracted attention. In a wireless IP phone system, a user moves in a wide range while making a call, like a mobile phone. The moved user maintains the call state while switching the access point.

However, when this wireless LAN network is used, unlike the wired connection, the terminal can be moved, so that it is necessary to ensure communication security and to perform a re-authentication process associated with access point switching, resulting in quality degradation. In general wireless LAN networks, there is a technique for simplifying re-authentication to an access point in order to shorten the time required for switching an access point (see, for example, Patent Document 1). It does not apply to telephone systems.
ITU-T Recommendation G.711-Appendix I: A high quality low-complexity algorithm for packet loss concealment with G.711. Sep, 1999. JP 2004-343448 A (page 2-3)

In a wireless IP phone, it is an important issue to enable a call similar to a conventional wired phone, that is, a real-time call without delay and loss. In the VoIP technology, as a solution when data delay and loss occur on the network, there is a technology that maintains the real-time property and quality by complementing the lost part with the previous and subsequent data by packet loss compensation. However, these cannot compensate for a loss of 50 ms or more.

In the case of a wireless IP telephone system, in addition to packet loss, access point switching accompanying movement occurs, and a delay time such as re-authentication processing occurs. When an access point is switched during a call, data delay and loss occur according to the processing time, and the quality deteriorates. If the processing time of movement is not a level that can be complemented by packet loss compensation, the call may be disabled.

Accordingly, the present invention has been made in order to solve the conventional problems as described above, and provides a telephone system that improves deterioration in voice communication quality when an access point is switched during a call. For the purpose.

In order to achieve the above object, the telephone system of the present invention uses a wireless LAN network having two or more access points that a wireless LAN terminal accesses through a wireless section and a LAN switch that relays data between the access points. In a telephone system that transmits audio signals using Internet protocols,
Each of the access points includes an authentication unit that authenticates access when the wireless LAN terminal accesses, and an authentication information storage unit that stores authentication information.
Equipped with an authentication information management server that stores and manages authentication information from each access point,
The access point stores the authentication information obtained by performing authentication by the authentication unit in its own authentication information storage unit and transmits it to the authentication information management server,
The authentication information management server stores the received authentication information and sends it to other access points.
The access point that has received the authentication information transmitted from the authentication information management server shall store the received authentication information in the authentication information storage means,
When there is an authentication request from an unauthenticated wireless LAN terminal, the access point authentication means transmits and receives information for authentication to the wireless LAN terminal, performs authentication using the shared key, and performs wireless communication. Authenticated information is sent to the LAN terminal, and when there is an authentication request with authenticated information added from the wireless LAN terminal, re-authentication is performed by referring to the authentication information stored in the authentication information storage means. It is characterized by that.

According to the present invention, it is possible to provide a telephone system that improves data loss and improves quality when switching access points.

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

In FIG. 1, reference numeral 10 indicates a wireless LAN terminal, and reference numerals 20, 30, and 40 indicate wireless L terminals.
The wireless LAN access point which AN terminal accesses through a radio area is shown. Wireless LA
N terminals 10a, 10b, and 10c indicate a state in which the same wireless LAN terminal 10 moves and is within the areas of wireless LAN access points 20, 30, and 40, respectively. Reference number 50
Indicates a LAN switch that is connected to the wireless LAN access points 20, 30, and 40 by wire and relays data between the wireless LAN access points 20, 30, and 40. Reference numeral 100
Indicates an authentication information management server of a wireless LAN terminal on the wireless LAN system. Reference numeral 200
Indicates a SIP server.

In the system targeted in this embodiment, when the wireless LAN terminal 10 connects to the wireless LAN system via the wireless LAN access points 20, 30 and 40, it has a function of performing an authentication method using a shared key. When the same wireless LAN terminal 10 authenticates the wireless LAN access points 20, 30, and 40, the shared keys used for authentication are matched.

The mutual communication between the wireless LAN terminal 10 and the call destination is realized by a call connection process by the SIP server 200. That is, after the connection between the wireless LAN terminal 10 having a call function and any of the wireless LAN access points 20, 30, and 40 is started and communication in the network layer, which is a protocol lower layer, is established, the SIP server 200 Call connection control based on the IP address is performed on the LAN terminal 10 and a counterpart terminal existing on the same network.

FIG. 2 is a response diagram when the unauthenticated wireless LAN terminal 10 connects to the wireless LAN access point 20.

In FIG. 2, the connection is made within the area of the wireless LAN access point 20. The wireless LAN terminal 10a sends an authentication frame 1 requesting to perform shared key authentication to the wireless LAN access point 20. The wireless LAN access point 20 that has received the authentication frame 1 sets the authentication information calculated by the shared key information in the authentication frame 2, and
It transmits with respect to the terminal 10a. The wireless LAN terminal 10a includes a wireless LAN access point 20
The received authentication information is recalculated using the shared key information, and the authentication frame 3 is transmitted to the wireless LA.
To N access point 20. The wireless LAN access point 20 has an authentication frame 3
The authentication frame 4 including the successful authentication is transmitted to the wireless LAN terminal 10a by confirming the validity.

By the above procedure, the wireless LAN terminal 10 can be connected to the wireless LAN system. Wireless LA
After connecting, the N terminal 10 starts mutual communication with the call destination via the SIP server 200, and then realizes the mutual call by peer-to-peer data transmission without passing through the SIP server 200.

When the authentication of the wireless LAN terminal 10 is completed, the wireless LAN access point 20
Data indicating that the wireless LAN terminal 10a has been authenticated by the wireless LAN access point 20 is registered in the wireless LAN terminal registration information database in the AN access point 20, and then the wireless LAN terminal 10a is registered with the authentication information management server 100. An information frame 5 indicating that the terminal 10 has been registered in the wireless LAN system is transmitted.

In the information frame 5, the MAC of the wireless LAN interface card of the wireless LAN terminal 10
Authentication result information for identifying the wireless LAN terminal 10 is based on the address, the SSID (Service Set ID), and the calculation result using the shared key when the wireless LAN terminal 10 authenticates the wireless LAN access point 20. The authentication information management server 100
Register authentication result information in the database in an authenticated state.

After the authentication information management server 100 registers the authenticated information in the database, the wireless LAN
An information frame 6 indicating that the wireless LAN terminal 10 has been authenticated in the wireless LAN system and exists in the area of the wireless LAN access point 20 is transmitted to the access points 30 and 40.

The wireless LAN access points 30 and 40 register that the wireless LAN terminal 10 has been authenticated at the wireless LAN access point 20 in the wireless LAN terminal registration information database managed by itself.

  Next, processing relating to movement of the wireless LAN terminal during a call will be described.

FIG. 3 is a response diagram when the authenticated wireless LAN terminal 10 connects to the wireless LAN access point 30.

A process when the wireless LAN terminal 10 moves from the area of the wireless LAN access point 20 and moves to the area of the wireless LAN access point 30 in FIG. 3 will be described. The radio sensitivity of radio wave output from the wireless LAN access point 20 with respect to the wireless LAN terminal 10b after movement is lowered. The wireless LAN terminal 10b switches connection to the wireless LAN access point 30 whose radio wave output is higher than that of the wireless LAN access point 20.

The wireless LAN terminal 10b is connected to the wireless LAN access point 30 in the movement destination area.
Execute authentication again. The wireless LAN terminal 10b includes a wireless LAN access point 30
At the time of authentication, an authentication frame 1 ′ obtained by adding authentication result information to the authentication frame 1 is transmitted as information indicating that the wireless LAN system has already been authenticated.

When the wireless LAN access point 30 that has received the authentication frame 1 ′ checks the authentication result information in the authentication frame 1 ′, the wireless LAN access point 30 itself manages the wireless L
It is confirmed whether the MAC address and SSID of the wireless LAN terminal 10 and authentication result information are registered on the AN terminal registration information database.

When the wireless LAN terminal 10 is registered on the database, the transmission / reception of the authentication frame 2 and the authentication frame 3 performed at the wireless LAN access point 20 is omitted, and the authentication frame 2 ′ is transmitted from the wireless LAN access point 30 to the wireless LAN terminal 10b. Transmit, wireless LAN terminal 1
Reconnection to the wireless LAN system of 0b is permitted.

After completing the re-authentication of the wireless LAN terminal 10b, the wireless LAN access point 30
Information of the wireless LAN terminal 10b is registered on the database in the wireless LAN access point 30, and an information frame 3 ′ is transmitted to the authentication information management server 100. The wireless LAN terminal 1
0 notifies that the movement of the wireless LAN access point 30 into the area has been completed.

The authentication information management server 100 receives registration information from the wireless LAN access point 30, updates the database in the server, and a registration information update frame indicating that the wireless LAN terminal 10 has moved with respect to the wireless LAN access points 20 and 40. 4 'is transmitted. By receiving the registration information update frame 4 ′, the wireless LAN access points 20 and 40 register that the wireless LAN terminal 10 is continuously authenticated in the wireless LAN system.

Thereafter, when moving from the area of the wireless LAN access point 30 and moving to the area of the wireless LAN access points 20 and 40, reconnection is performed using the above method.

The wireless LAN terminal that has been re-authenticated by the above-described method can continue to make a call in the upper application layer due to the reconnection.

As is apparent from the above, according to the present embodiment, the wireless LAN system includes a wireless LAN.
By shortening the re-authentication time due to the movement of the terminal, it becomes possible to reduce the loss of real-time data such as voice data.

Although the present invention is configured as in the above-described embodiment and can improve the voice quality even if it is implemented alone, it can also be implemented in combination with other conventional techniques for improving the voice quality.

The present invention is not limited to the above embodiment. For example, instead of using a SIP server for the call control server, the call control protocol is H.264. A VoIP system may be constructed using a server that performs call control using H.323, that is, a gatekeeper.

Furthermore, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a system diagram showing an embodiment of a telephone system according to the present invention. The sequence diagram which shows the authentication procedure in one Embodiment of this invention. The sequence diagram which shows the re-authentication procedure in one Embodiment of this invention.

Explanation of symbols

10 Wireless LAN terminals 20, 30, 40 Wireless LAN terminals in the area of wireless LAN access points 10a, 10b, 10c
50 LAN switch 100 Authentication information management server 200 SIP server

Claims (1)

In a telephone system that uses a wireless LAN network having two or more access points that a wireless LAN terminal accesses through a wireless section and a LAN switch that relays data between the access points, and transmits voice signals using the Internet protocol ,
Each of the access points includes an authentication unit that authenticates access when a wireless LAN terminal accesses, and an authentication information storage unit that stores authentication information.
Equipped with an authentication information management server that stores and manages authentication information from each access point,
The access point stores authentication information obtained by performing authentication by an authentication unit in its own authentication information storage unit and transmits it to the authentication information management server,
The authentication information management server stores the received authentication information and transmits it to another access point,
The access point that has received the authentication information transmitted from the authentication information management server shall store the received authentication information in the authentication information storage means,
When there is an authentication request from an unauthenticated wireless LAN terminal, the access point authentication means exchanges information for authentication with the wireless LAN terminal, performs authentication using a shared key, and Authenticated information is transmitted to the wireless LAN terminal, and when there is an authentication request with the authenticated information added from the wireless LAN terminal, re-authentication is performed with reference to the authentication information stored in the authentication information storage means A telephone system characterized by that.