JP4309382B2 - Wireless telephone system - Google Patents

Description

  The present invention relates to a wireless telephone system used for an extension telephone system in an office. In particular, the present invention relates to a radiotelephone system that performs voice communication between terminals using IP (Internet Protocol).

  A system (hereinafter referred to as an IP telephone system) that transmits voice data in an IP packet (hereinafter referred to as an IP telephone system) has been introduced in companies and general households (see, for example, Patent Document 1). Compared with a circuit-switched telephone service that requires expensive resources such as an exchange, a low-priced telephone service can be provided by using an IP network that can use communication resources at low cost. In recent years, a telephone terminal is connected to an IP network using a wireless local area network (LAN) technology to further increase the mobility of the telephone terminal.

  By the way, since the IP network is a best-effort type network, the transmission quality is deteriorated due to packet discard or delay variation (jitter). These problems can be compensated to some extent by the buffering function on the receiving side. However, when excessive deterioration occurs, there is a problem that sound is interrupted, noise and echoes are generated. In particular, the wireless LAN section is likely to become a bottleneck, and packet discard and delay variation frequently occur.

  Packet discards and fluctuations in the amount of delay are caused by various causes, and the main one is that the number of connected calls becomes excessive and exceeds network resources. IP telephones include SIP (Session Initiation Protocol) and H.264. Incoming and outgoing calls are controlled by a communication control protocol such as H.323, but if the number of call connections is increased without considering network resources, packet discard and delay amount fluctuations gradually occur and voice quality begins to deteriorate.

On the other hand, it is conceivable to limit the upper limit of the number of calls to be connected to suppress the resource excess and to suppress the deterioration of communication quality. For example, in a wireless LAN section, there is a method of limiting the number of terminals accommodated in one access point. However, in a wireless LAN, the modulation method (data rate) is adaptively changed for each terminal depending on the state of the transmission path between the access point and the wireless IP telephone, so that quality cannot be managed only by managing only the number. For example, in an IEEE802.11b wireless LAN, it takes about 11 times longer to transmit the same data at the lowest rate of 1 Mbps compared to the maximum rate of 11 Mbps. Therefore, in a state where one wireless IP phone is connected, a terminal communicating at 11 Mbps and a terminal communicating at 1 Mbps consume 11 times more resources. For this reason, sufficient communication quality cannot be obtained by simply limiting the number of accommodated units.
JP 2001-285342 A

As described above, the existing wireless IP telephone system has fatal problems such as deterioration in call quality due to the use of the IP network and difficulty in making maximum use of communication resources in the wireless section.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless telephone system capable of maximizing use of network resources in a wireless section while ensuring call quality.

According to one aspect of the present invention in order to achieve the above object, a resource management server for managing a plurality of telephone terminals including the wireless telephone terminals connected to the communication network via the access point, the resources of the communication network And a call connection server for processing a call connection between the telephone terminals, and adaptively changing a modulation scheme in a radio path between the access point and the radio telephone terminal according to a situation of the radio path When the call connection request occurs, the call connection server inquires of the resource management server about whether or not the call can be connected and obtains permission, and the resource management server and resource management database for managing individual resources of a plurality of paths forming the communication network, a wireless telephone in connection to the access point A wireless telephone management database for managing a wireless path and a data rate for each terminal, and a communication path specifying means for specifying a communication path between a caller and a callee from the resource management database based on an inquiry from the call connection server Calculating means for calculating resources of the radio path consumed when a call is connected in response to the call connection request based on the radio telephone management database when the communication path includes a radio path; When it is determined whether the call quality can be ensured when the resource calculated by the calculation means is consumed based on the data rate managed in the wireless telephone management database, and the call quality can be secured And a determination means for permitting call connection to the call connection server.

  By taking such measures, when a call connection request occurs, the communication path between the caller and the callee is specified, and if a radio path exists in this path, The call connection is permitted only when the call quality can be secured even if the call connection is made. Accordingly, it is possible to prevent a call exceeding the radio path resource from being connected, and it is possible to provide a radio telephone service that can use the network resources to the maximum while ensuring the call quality.

  According to the present invention, it is possible to provide a wireless telephone system capable of maximizing the use of network resources in a wireless section while ensuring call quality.

  FIG. 1 is a system diagram showing an embodiment of a telephone system according to the present invention. In FIG. 1, reference numeral 1 is an SIP (Session Initiation Protocol) server, 2 is a resource management server, 3a and 3b are wireless LAN (Local Area Network) access points, 4a, 4b and 4c are routers, and 5a and 5b are layer 2s. Switches 6a, 6b, 6c, 6d, 6e, and 6f are wireless IP telephones, 7a and 7b are data terminals, and 8a, 8b, 8c, and 8d are IP telephones. Among these, the routers 4 a to 4 c function as nodes forming the IP network, and in particular, the router 4 c is connected to the Internet network via the communication path 21. In FIG. 1, reference numerals 9 to 23 are attached to the respective paths constituting the IP network. The data terminals 7a and 7b mainly exchange data other than voice, such as e-mails, but a function as a telephone can be realized depending on the application software installed.

  The routers 4a and 4b are respectively installed in office premises located at a relatively long distance, and mediate information communication between offices via the router 4c. That is, the wireless LAN access point 3a and the layer 2 switch 5a below the router 4a are arranged in the same office premises, and accommodate the wireless IP telephones 6a, 6b, 6c, the data terminal 7a, and the IP telephones 8a, 8b. Similarly, the wireless LAN access point 3b and the layer 2 switch 5b below the router 4b are disposed in the same office premises and accommodate the wireless IP telephones 6d, 6e, 6f, the data terminal 7b, and the IP telephones 8c, 8d.

  An extension call within the same office and an outside line call between offices via the IP network are realized by call connection processing by the SIP server 1. That is, the SIP server 1 performs call connection control based on the IP address for the wireless IP telephones 6a to 6f, the data terminals 7a and 7b, and the IP telephones 8a, 8b, 8c, and 8d, thereby realizing mutual communication. In particular, when the SIP server 1 receives a call request specifying a destination terminal from these telephone terminals, the SIP server 1 inquires the resource management server 2 about whether or not call connection is possible, and connects the call only when the call is permitted. In response to this inquiry, the SIP server 1 notifies the resource management server 2 of the IP address of the calling terminal and the IP address of the called terminal. The resource management server 2 stores various databases for managing communication resources in the IP network in the database unit DB.

  FIG. 2 is a functional block diagram showing the resource management server 2 of FIG. The resource management server 2 includes a monitor unit 31, an input / output unit 32, an interface unit 33, a main control unit 34, and a database unit DB. Among these, the monitor unit 31 displays various network management information, for example, and has a user interface function together with the input / output unit 32. The interface unit 33 is connected to the router 4a in FIG. 2 and has an interface function for exchanging various information with the IP network via the router 4a.

The database unit DB stores a network configuration database DB1 and a wireless IP telephone management database DB2. The network configuration database DB1 is used for individually managing transmission capacities (resources) of the paths 9 to 23 forming the IP network. As shown in the following table, in the network configuration database DB, resources (transmission capacity) and section information are recorded in association with each path. The resource of the path may change according to the network design, and the resource management server 2 sequentially grasps the resource of each path by periodically inquiring each node. The section information is defined by nodes at both ends of the path. Note that the resources in the wireless section are managed by the data rate and the number of connections that can be accommodated.

The wireless IP telephone management database DB2 is used for managing the access point of the connection destination and the data rate for each wireless IP telephone connected to the IP network. As shown in the following table, for example, the wireless IP telephone 6a is connected to the access point AP3a at a data rate (modulation method) of 11 Mbps. The wireless IP telephones 6c and 6d are not connected to the IP network and are blank in the database.

  Next, the main control unit 34 includes a communication path identification processing unit 34a, a calculation processing unit 34b, and a determination processing unit 34c as its software processing functions. Based on the inquiry from the SIP server 1, the communication path specifying processor 34a specifies the communication path between the caller and the callee from the network configuration database DB1. Based on the radio IP telephone management database DB2, the calculation processing unit 34b uses the radio IP telephone management database DB2 to determine the radio path resources consumed when a call is connected in response to a call connection request when the specified communication path includes a radio path. calculate. The determination processing unit 34c determines whether or not the call quality can be ensured when the calculated resource is consumed, and permits the SIP server 1 to establish a call connection only when the call quality can be ensured. Next, the operation of the above configuration will be described.

  In FIG. 1, for example, it is assumed that a call request is made from the IP telephone 8a to the wireless IP telephone 6d as a call destination. This call request includes the IP addresses of the IP telephone 8a and the wireless IP telephone 6d, and is sent from the IP telephone 8a to the SIP server 1. The SIP server 1 inquires of the resource management server 2 whether or not call connection based on this call request is permitted. This inquiry also includes the IP addresses of the IP telephone 8a and the wireless IP telephone 6d.

  The resource management server 2 that has received the inquiry refers to the network configuration database DB, and the paths existing in the communication path connecting the IP telephone 8a and the wireless IP telephone 6d are paths 12, 10, 19, 20, 14, and 23. Make sure. Here, the existence of the wireless path 23 is confirmed. The resource management server 2 inquires of the access point 3b about the number of wireless IP telephones currently connected and the respective modulation methods, and updates the wireless IP telephone management database DB2. According to Table 2, it can be confirmed that the wireless IP telephones 6e and 6f are connected, and both are connected at a data rate of 5.5 Mbps.

  Based on these pieces of information, the resource management server 2 determines whether or not call quality is possible even when a new call connection is connected. In the network configuration database DB1 of Table 1, it is registered that the call quality can be secured even if a maximum of five terminals are connected with respect to the resources of the wireless path 23 if the terminals are connected at 11 Mbps. However, as confirmed earlier, there are already two wireless IP telephones communicating at 5.5 Mbps on this path, so one terminal of 11 Mbps can be connected, but cannot be connected at 5.5 Mbps or lower. Is determined. The resource management server 2 considers the data rate of the wireless IP telephone 6d and notifies the SIP server 1 that connection is possible only when the resource consumption is within the limit. The SIP server 1 performs connection processing if the notification result from the resource management server 2 is connectable, and does not perform connection processing if the notification result is not possible.

  With the above operation, the number of calls can be limited in consideration of the modulation method (data rate) at which each wireless IP telephone is connected to the access point to which it is connected, and calls are connected more than resources in the wireless section. Can be prevented. Therefore, it is possible to provide a radio telephone system that can make maximum use of network resources in the radio section while ensuring call quality.

  The present invention is not limited to the above embodiment. For example, when the IP addresses of the wireless IP telephones 6a to 6f are managed by a DHCP (Dynamic Host Configuration Protocol) server, the access point to which each wireless IP telephone is connected is determined based on the MAC (Media Access Control) address. Registration with the management server 2 is performed. When the IP address is notified from the SIP server 1, the resource management server 2 obtains the MAC address information of the corresponding IP address from the DHCP server, and knows the access destination of each wireless IP telephone based on the MAC address. .

  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 functional block diagram which shows the resource management server 2 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... SIP server, 2 ... Resource management server, 3a, 3b ... Wireless LAN access point, 4a, 4b, 4c ... Router, 5a, 5b ... Layer 2 switch, 6a, 6b, 6c, 6d, 6e, 6f ... Wireless IP Telephone, 7a, 7b ... Data terminal, 8a, 8b, 8c, 8d ... IP telephone, 9-23 ... Pass, 31 ... Monitor, 32 ... I / O, 33 ... Interface, 34 ... Main controller, 34a ... Communication path identification processing unit, 34b ... calculation processing unit, 34c ... determination processing unit, DB1 ... network configuration database, DB2 ... wireless IP telephone management database

Claims (2)

A plurality of telephone terminals including the wireless telephone terminals connected to the communication network via the access point, and resource management server for managing the resources of the communication network, a call connection server for processing a call connection between the telephone terminal A radio telephone system that adaptively changes a modulation scheme in a radio path between the access point and the radio telephone terminal according to a situation of the radio path;
The call connection server is:
When a call connection request occurs, the call is connected only when permission is obtained by inquiring the resource management server whether the call can be connected,
The resource management server
A resource management database for individually managing resources of a plurality of paths forming the communication network;
A radio telephone management database for managing radio paths and data rates for each radio telephone terminal connected to the access point ;
A communication path specifying means for specifying a communication path between a caller and a callee from the resource management database based on an inquiry from the call connection server;
Calculating means for calculating resources of the radio path consumed when a call is connected in response to the call connection request based on the radio telephone management database when the communication path includes a radio path;
When it is determined whether the call quality can be ensured when the resource calculated by the calculation means is consumed based on the data rate managed in the wireless telephone management database, and the call quality can be secured And a determination means for permitting call connection to the call connection server. The radio telephone system according to claim 1, wherein the resource management server manages the radio path resource in association with a modulation scheme of the radio path.

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