WO2002084963A1

WO2002084963A1 - Unified wireless communication system for private network

Info

Publication number: WO2002084963A1
Application number: PCT/KR2001/000800
Authority: WO
Inventors: Oh-Sang Kwon; Chang-Dong Son; Seong-Cheol Kim; Jin-Soo Han
Original assignee: Sei Yang Net Communication Co., Ltd.
Priority date: 2001-04-12
Filing date: 2001-05-17
Publication date: 2002-10-24
Also published as: KR20020079006A

Abstract

UWS (Unified Wireless System) is to replace the wired network with wireless one to integrate the voice and data (including video data) service in one system. The currently dominant IP-based public communication network designed and useful mainly for voice service is using peer-to-peer protocol agreement architecture such that lacks of QoS (Quality of Service) of the transmitted packets to be vulnerable to hacker's attack. This kind of security problem is one of the facts proving the importance of private network. UWS is the intelligent communication system to provide the customers with the wireless and private network integrating voice and data service resulting into saving the network construction and maintenance cost. UWS is easily extensible to the public CDMA-based communication network with the end-user terminal able to handle both private and public network protocols properly.

Description

UNIFIED WIRELESS COMMUNICATION SYSTEM FOR PRIVATE

NETWORK

Technical Field

The present invention relates to a unified wireless communication system for a private network, and more particularly, to a unified wireless communication system for a private network, which allows the private network divided into a wired voice communication and a wired data communication to be capable of providing an intelligent and composite function.

Background Art

The general private network is macroscopically divided into a wired voice communication network and a data communication network.

First, the voice communication network enables the private voice communication and a calling access to the outside when a private exchanger having a proper capacitance and a key-phone are provided.

Since the wired voice communication network needs to install terminals, such as a key-phone or the like connected through the telephone line at fixed positions, users can carry out the voice communication only at the fixed positions where the terminals are installed. To this end, this wired voice communication network causes a load in the initial installing period and cost, so that there is generated a drawback in that the communication network cannot cope with a variation in the environment pliably.

Second, the data communication currently enables an access to the Internet or Intranet by installing devices, such as router, hub, Ethernet card, cable and the like at fixed positions within the private business field.

Thus, since these various devices for the data communication are connected and installed, there is a disadvantage in that it is inconvenient to establish a system depending on the movement of the devices and the variation of the environment.

Like the above, since the private communication network has the voice communication network and the data communication network physically separated from each other, there are caused a difficulty in the maintenance and repair, a double cost burden and a user's fixity.

Accordingly, while the data communication service using the Internet is distributed as an essential environment in the life of the communication users in the recent years, voice communication and data communication technologies using the Internet are recently being highlighted.

So, in order to solve the aforementioned problems of the private communication network, there appears and is being developed a wired VoIP (Voice over Internet Protocol), which integrates the voice communication between the LANs using the wired network with the data communication. However, although the VoIP technology enables the system integration, since the technology requires to install the terminals or communication devices using the wired network at fixed positions, it has various limitations, such as the fixity of the user, non-flexibleness in the installment and variation in the environment, a technology problem of the service provider for the VoIP, a network capacitance problem, a compatibility of the terminals in end-to end, etc. To this end, the VoIP technology is currently not used as means for solving the problems of the separated private communication network.

Also, there is being developed an integration technology of the data communication network and the voice communication network using IP on the wired.

However, since this integration network using the IP has a structure in which the network is connected by a VoIP provider for the inner and outer communication, is provided a service, and does not provide an inner switching function, a telephone access capable of guaranteeing a voice quality on service becomes possible only if an additive device is provided. Further, the integration network is a centralized network and has a problem in that a private calling and an external calling access are completely cut when the service is stopped due to the service provider's problem, so that it becomes impossible to establish the private network.

Furthermore, although the integration network way enables the integration of the voice and the data on the wired communication network, it is inconvenient to operate the private voice network, there is caused a problem in the spatial limitation of the user due to the fixity of the wired, and an installing problem of devices still remains.

Moreover, since the private voice communication can be leaked, there exist problems on security and installation.

Like the above, in order for a user to use a telephone access service in the private network established by the wired, there is needed an establishment and management of a PSTN (Public Switching Telephone Network) access device, and in order to use a data communication network access service, there is needed an establishment and management of a PSDN (Public Switching Data Network) access device separated from the PSTN access device.

So, recently, there is proposed an integration way of the telephone access and the data communication network access using the VoIP service. However, since this integration way becomes possible only by a point to point access between the service provider and the subscriber, an organization consisting of a plurality of groups needs to be provided a special private exchange function service of the VoIP provider in order to use the private exchanger function. Further, since the integration way has a problem in the security due to the communication with the external provider for an interphone. Thus, the integration way has the insoluble problems, such as the cost problem due to the additive device installation, the management problem, the installation and time problems in establishing the network due to the spatial limitation of the user, and a frequent arrangement alteration and movement, and the economical and time problems due to the extension of the network.

Disclosure of the Invention Accordingly, the invention has been devised to solve the problems associated with the conventional wired network, i.e., an excessive investment in the cost due to a dual installation of devices for establishment of the network, and it is an object of the invention to save the investment cost for the establishment of the network by integrating devices for the voice service and data service.

It is another object to provide an operation manager with a convenience for the maintenance and repair and to save the cost for the maintenance and repair by integrating the divided telephone access network and data access network to remove an occurrence problem of the dual maintenance and repair cost and difficulty of the dual maintenance and repair, and enable a centralized network management. Also, since the conventional network is made in a complicated wired connection between the system and the terminal, it is inevitable to invest a further economical cost and working time on reconstituting the network due to the alteration of the network constitution, the position movement of the terminals and the adding of the terminal. The invention enables an access to the network on the spot of the installation without an additive work in the network extension or the movement of the terminal and can use the data service and the telephone access service.

For a small sized business field to use the telephone access service using the wired VoIP provider, there is essentially requested the use of the exchanger of the service provider, and the security on an inner secret of the organization is opaque. Whereas the invention establishes the integration service of the telephone access service and the data service, using the VoIP technology in the wireless environment with the private network, to enable to provide services independent on a variation and to solve the convenience of the telephone access/inner data communication, the transparency of the network, and the security of the private data raised recently.

Also, the invention facilitates to realize the wireless image communication, which is anticipated in the IMT-2000, and can provide unlimited services by integrating the inner network management, the subscriber management and the additional service for the users, including the conventional private web server and mail server functions for additionally enhancing the use degree of the user network, by a single network, and grafting the VoIP technology in the local network.

Further, the invention gradually integrates the small sized wireless LANs, to thereby enhance the network use efficiency, provide the simplified network management effect, enhance the service quality, save the service cost, provide a convenient network management, and provide the national economy with a vast interest instead of infra-network obtained through a vast investment.

To accomplish the above objects, there is provided a unified wireless communication system for a private network, comprising: a plurality of terminals for providing a user with voice, image and data communication services; a plurality of wireless connection modules wireless-connected with the plurality of terminals; a switching module for switching the plurality of wireless connection modules so as to receive and transmit data inputted and outputted through a public switching data network (PSDN) and a public switching telephone network (PSTN) from and to the plurality of terminals; a routing module for accessing to the Internet through the PSDN; and a server for providing a call processing for inner and outer voice communications through the PSTN and the PSDN, a data transmitting/receiving processing, a maintaining and repairing processing and a usage convenience for an operator.

The server preferably comprises: a call processing module for performing an inner VoIP call access and a call access to the PSTN; a gateway module for processing voice data transmission and receipt between the PSTN and the terminals; and a working maintaining module for maintaining and repairing a device constituting the unified wireless communication system, and for providing the operator with the convenience.

The wireless connection module preferably uses an ISM band that is a non-approved frequency band based on IEEE 802.11 series standards.

The wireless connection module is a wireless LAN way and uses a wireless technology of a DSSS way.

Also, an interface for a control signal between the wireless connection module and the server is a SNMP having an IETF RFC 1157 standards.

The call processing module comprises: a call control module for performing call setting and releasing functions for the inner and outer voice communications, and the data communication of the terminals; a registration module for performing a subscriber registration; a data transmitting module for transmitting and receiving the voice and fax data through a connection set with an outside; a directory service module for performing a conversion of an IP address and a phone number for a telephone service in an IP environment; and a gateway module for performing a telephone access and a data processing between the terminals having the wireless IP network environment and the subscriber of the public switching telephone network.

Further, the working maintaining module comprises: a system error managing module for collecting a general error state of the system, including an error processing for a hardware device constituting the system, and an error processing depending on a usable call resource state for the communication service so as to guarantee a smooth service of the terminal on service; an operator matching module for providing the operator with the convenience for the management, maintenance and repair with respect to various functions for devices and network management of the system; a performance managing module for reporting a collection of a reliable raw data with respect to an element affecting decision of the performance, and a statistical data for evaluating the system performance using the collected data; a constitution managing module for making flexible the constitution of the system depending on the characteristic of a site to which the system is applied, and extending the system or enhancing the service quality; an authenticating module for performing an authentication for a subscriber who uses an authentication method in the wireless environment together with a user authentication method used in an SIP; and a charge processing module for collecting data with respect to use charge of the network and estimating the charge depending on use frequency of the network.

The invention makes the private network of the integration service through a wireless LAN based on IEEE 802.11 series standards so as to provide the telephone access service and the data communication service, and provides the telephone access between the inner users, the inner voice communication, the image communication and the data communication using the VoIP technology based on the private network.

Brief Description of the Drawings Fig. 1 is a view schematically showing a unified wireless communication system for a private network in accordance with the present invention;

Fig. 2 is a schematic view showing a concrete logical structure for a server of the unified wireless communication system for the private network in accordance with the present invention; Fig. 3 is a schematic view of an interface standard between the system elements matched with the system structure so as to perform voice/image/data communication serviced in the unified wireless communication system for the private network;

Fig. 4 is a schematic view showing a protocol of the unified wireless communication system for the private network on the basis of an OSI class in accordance with the present invention; Fig. 5 is a block diagram concretely showing a server of the unified wireless communication system for the private network in accordance with the present invention;

Fig. 6a to Fig. 6c are flow charts for illustrating a registration method by an SIP protocol between the private terminal of the unified wireless communication system and the server; and

Fig. 7a to Fig. 7c are flow charts for illustrating a voice call flow of the unified wireless communication system and the server for the private network in accordance with the present invention.

Best Mode for Carrying out the Invention

Hereinafter, there are described in detail preferred embodiments with reference to the accompanying drawings. The preferred embodiments are not to limit the claims of the invention, but they are provided only as examples.

Fig. 1 is a view schematically showing a unified wireless communication system for a private network in accordance with the present invention.

As shown in Fig. 1, the unified wireless communication system includes: a plurality of terminals 50 for providing a user with voice, image and data communication services; a plurality of wireless connection modules 40 wireless-connected with the plurality of terminals 50; a switching module 30 for switching the plurality of wireless connection modules 40 so as to receive and transmit data inputted and outputted through a public switching data network (PSDN) and a public switching telephone network (PSTN) from and to the plurality of terminals 50; a routing module 10 for accessing to the Internet through the PSDN; and a server 20 for providing a call processing for inner and outer voice communications through the PSDN and the PSTN, a data transmitting/receiving processing, a maintaining and repairing processing and a usage convenience for an operator.

Fig. 2 is a schematic view showing a concrete logical structure for a server of the unified wireless communication system for the private network in accordance with the present invention. Referring to Fig. 2, the unified wireless communication system includes: a plurality of terminals 50 for providing a user with voice, image and data communication services; a plurality of wireless connection modules 40 wireless-connected with the plurality of terminals 50; a switching module 30 for switching the plurality of wireless connection modules 40 so as to receive and transmit data inputted and outputted through a public switching data network (PSDN) and a public switching telephone network (PSTN) from and to the plurality of terminals 50; a routing module 10 for accessing to the Internet through the PSDN; and a server 20 for providing a call processing for inner and outer voice communications through the PSDN and the PSTN, a data transmitting/receiving processing, a maintaining and repairing processing and a usage convenience for an operator. The server 20 includes: a call processing module 22 for performing an inner

VoIP call access and a call access to the outer PSTN; a gateway module 26 for processing a voice data transmission and receipt between the outer PSTN and the terminals 50; and a working maintaining module 24 for providing the operator with the maintenance and repair for a device constituting the unified wireless communication system, and the convenience with the operator.

In the above system, the terminal 50 includes a PDA, a notebook, a wireless terminal, a desktop PC, etc.

Fig. 3 is a schematic view of an interface standard between the system elements matched with the system structure so as to perform voice/image/data communication serviced in the unified wireless communication system for the private network.

In Fig. 3, interface standards between the elements of the system are shown together with arrows.

First, an interface between the plurality of terminals 50 and the wireless connection module 40 has an IEEE 802.11 series standard, and a wireless LAN way. The wireless technology uses a DSSS (Direct Sequence Spread Spectrum) way, which converts a narrow band signal into a wide band signal by applying a diffusion code having a sufficiently wide spectrum compared with a band width of a signal for diffusing spectrum. Second, an Ethernet standard, IEEE 802.3 is used between the wireless connection module 40, the switching module 30, the server 20 and the routing module 10.

Third, a control signal interface between the wireless connection module 40 and the server 20 uses an IETF (Internet Engineering Task Force) RFC (Request For Comments) 1157 standard, SNMP (Simple Network Management Protocol). Fourth, an interface between the terminals 40, or between the terminals 40 and the server 20 includes: a control interface module for performing a call processing; a voice processing interface module for processing a voice data between the private terminals 50 and subscribers of the PSTN; and a voice signal processing interface module for a voice communication between the private terminals. The unified wireless communication system for the private network is a system for providing an IP network with a service in a wireless LAN environment, and provides such the service using the VoIP interface standards.

First, the control interface module uses an IETF RFC 2543 standard, SIP (Session Initiation Protocol). Next, the voice data processing interface module for the voice data between the private terminals 50 and the PSTN subscriber processes transmission and receipt of the voice data using an IETF RFC 1889-1900 standard, Real-Time Protocol (RTP) for transmitting and receiving data in real-time and a real-time control protocol for guaranteeing a service quality of real-time data in an IP network. Further, the voice signal processing interface for processing voice signals between the private terminals 50 is a technology for displaying a voice signal as a digital signal through quantization of a sampling signal and a pulse size quantization on the time axis with the waveform coding technology, and is based on G.711 recommended by ITU-T for PCM (Pulse Coded Modulation)-decoding a voice frequency signal. Additionally, the voice signal processing interface decides pitch and code book parameters using an analysis/synthesis structure having a basic structure of CE-LP algorithm so as to enhance efficiency in the band width of the data transmission and receipt, and stores the code book by vector-quantizing an excited signal. The CE-LP algorithm is discriminated from a general CELP structure in that the conjugate code book signal and the excited signal are expressed by an algebraic and thus is 2-steps vector-quantized. The voice signal processing interface adopts G.729 Annex A (CS-ACELP: Conjugate Structure Algebraic Code Excited Linear Prediction) recommended by ITU-T and having advantages in that enhancement effect in the voice quality and decrease effect in calculation amount are generated by the conjugate structure and the algebraic expression, and the voice signal can be encoded without lowering in the voice quality with a low transmission rate.

In the unified wireless communication system for the private network of the present invention, the voice encoding way basically adopts G.711 recommended by

ITU-T, and additionally G.729 Annex A (CS-ACELP) recommended by ITU-T so as to enhance the voice quality and the efficiency in the communication band width and to be matched with the next generation communication standards IMT-2000.

Fifth, an interface between the private terminals 50 and the PSTN includes a signal interface module for processing voice and data signals between the private terminals 50 and the PSTN, and a voice/data interface module for transmitting and receiving voice and data between the private terminals 50 and the PSTN. The signal can interface module discriminates an access method of the PSTN depending on a place where the unified wireless communication system for the private network is being worked.

In other words, a small-scaled business field can use the service by using main lines of 4 - 8, and uses a signal way of DTMF (Dual Tone Multi Frequency). A large-scaled business field provides the service for the access to the PSTN using El trunk and a signal way of R2MF.

Further, the voice/data interface between the unified wireless communication system for the private network and the PSTN is a technology for displaying a voice signal as a digital signal through quantization of a sampling signal and a pulse size quantization on the time axis with the waveform coding technology, and uses G.711 recommended by ITU-T for PCM (Pulse Coded Modulation)-decoding a voice frequency signal.

Fig. 4 is a schematic view showing a protocol of the unified wireless communication system for the private network on the basis of an OSI class in accordance with the present invention.

As shown in Fig. 4, the protocol operating in the unified wireless communication system for the private network is made to implement wireless LAN environment and IP telephone system basically, and is based on an Internet protocol for the voice, image and data communications on the wired and wireless LAN. The protocol of Fig. 4 is described on the basis of the OSI class. Class 2 is a data link class, makes a role in converting an electrical signal outputted from a network card to a network frame, transmits the frame from one computer to another computer, uses a wireless port of IEEE 802.11 series standard and a wired port of IEEE 802.3 standard.

Class 3 is a network class, makes a role in restoring a logic address to a physical address, and uses IPv4 (Internet Protocol Version 4) standards in deciding a route where a targeted computer is positioned.

Class 4 is a transport class, carries out an error detection and restoration, divides a long message into small-sized several packets if necessary and transmits the divided packets, reassembles the divided packets, and uses TCP (Transmission Control Protocol), and UDP (User Datagram Protocol).

Class 5 is a session class, participates in all procedures in which different computers make a session, perform a work, and end the work, and uses SNMP (Simple Network Management Protocol), SIP (Session Initiation Protocol), RTP (Real Time Protocol), and RTCP (Real Time Control Protocol). Class 6 is a presentation class, converts data received from an application class into an intermediate stepped format, carries out data encryption/encoding/compression, and uses G.711 recommended by ITU-T, G.729A, MPEG (Motion Picture Experts Group) recommended by ITU-T.

Class 7 is an application class, translates data into an intermediate stepped format, and uses a protocol for processing data, voice and image.

Fig. 5 is a functional block diagram concretely showing a server of the unified wireless communication system for the private network in accordance with the present invention.

As shown in Fig. 5, the server 20 including the call processing module 22 and the working maintaining par 24 is divided into functional modules and the functional modules are shown in detail. First, the call processing module 22 includes: a call control module 221 for performing call setting and releasing functions for the inner and outer voice communications and the data communication of the terminals; a registration module 222 for performing a subscriber registration; a data transmitting module 223 for transmitting and receiving voice and fax data through a connection set with an outside; a directory service module 224 for performing a conversion of an IP address and a phone number for a telephone service in an IP environment; and a gateway module 26 for performing a telephone access and a data processing between the terminals having the wireless IP network environment and the subscriber of the PSTN. The aforementioned respective elements of the call accessing module 22 are again concretely described.

First, the call control module 221 processes a call setting and a call ending between the terminals requesting a calling in the unified wireless communication system for the private network identically with respect to the server 20 and the terminals. For the call signal, the protocol of SIP is used, and the call setting is performed through

3 -way handshake method.

Second, the registration module 222 performs a management of the subscribers for effective management of operating network band and security of inner data with respect to a desktop PC, a notebook PC, and a PDA (Personal Data Assistant) each provided with a wireless LAN card which are serviceable in IEEE 802.11 series

^• wireless LAN environment such that it is serviceable in the unified wireless communication system for the private network.

ISM band which is a frequency band used in the unified wireless communication system for the private network is a non-approved frequency band, is serviceable to whoever has terminals matched with IEEE 802.11 series standards, and thus affects on a proper service for subscribers pertaining to the established network. To this end, there are essentially requested a management of the subscribers who request voice communication image communication/data communication in the wireless LAN environment, an effective management of operating network band, and a management on the security of the inner data.

Accordingly, there is a management method commonly applied to the terminals 50 and the server 20. Registration procedure thereof is performed by inputting various information of a user according to the manager's command who manages the network in a database, transmitting an MAC (Media Access Control) address that is the information of the inputted terminal 50 using SNMP which is a standard deliberated with the wireless connection module 40, to the wireless connection module 40, and registering the transmitted MAC address in a connection table of the wireless connection module 40 so as to be used.

Also, in case that service area is changed and the power of the terminal 50 is turned off due to the mobility of the terminal in the wireless environment operating with the multiple wireless connection modules 40, a user registered in the subscribed database can again register by matching the terminal's information with the SIP protocol and transmitting the matched information to the server 20 to update the user's registered information.

^• Fig. 6 is a flow chart for illustrating a registration method between the private terminal and the server in the unified wireless communication system for the private network in accordance with the present invention.

Specifically, Fig. 6a is a flow chart showing an initial registration procedure of the terminal, Fig. 6b is a flow chart showing a registration procedure according to an alteration of a contact list of the terminal, and Fig. 6c is a flow chart showing a procedure for releasing the registration of the terminal.

First, as shown in Fig. 6a, in the initial registration procedure of the terminal, the terminal 50 transmits a registration request signal including a contact list thereof to the server 20. The server 20 requests information for the authentication to the terminal 50. The user transmits encoded authentication information to the server 20 using a user ID and a secret number. The server 20 performs the authentication using the authentication information inputted from the terminal 50. As a result of the authentication, if the user is a normal user, the registration is completed, and an OK signal is transmitted to the terminal 50.

Next, as shown in Fig. 6b, in the registration procedure depending on the alteration the contact list of the terminal, the terminal 50 transmits a registration request signal to the server 20 using updated contact list and user information. The server 20 performs the registration depending on whether or not the user information is normal or abnormal, and transmits the registration result to the terminal 50. If the terminal 50 is normal, the contact list is updated, and if the terminal 50 is abnormal, a non-approval signal of the alteration is transmitted to the terminal 50. Further, as shown in Fig. 6c, in the procedure for releasing the registration of the terminal, the terminal 50 transmits an ending signal and the user information to the server 20. The server 20 performs the registration depending on whether or not the user information is normal or abnormal, and transmits the registration result to the terminal 50. If the terminal 50 is normal, the contact list is deleted, and if the terminal 50 is abnormal, a non-approval signal of the release is transmitted to the terminal 50.

Third, the data transmission module 223 sets a data connection for data transmission and receipt, and enables transmission and receipt of voice data between the terminals 50 requesting a calling, if a call setting is carried out between the terminals 50 through the call control module. At this time, the setting is commonly carried out with respect to the server 20 and the terminal 50 using RTP and RTCP.

Fourth, the directory service module 224 manages an IP address matched with a telephone number database, provides the IP address if the terminal 50 requests the IP address, grasps the positions of the registered terminals 50, and updates and manages the information of the terminals 50 in conjunction with the registration module 222. In other words, the unified wireless communication system for the private network of the present invention is a system of a LAN environment, and the respective terminals 50 thereof are assigned inherent IP addresses to use services. Accordingly, since the respective terminals 50 use only the telephone number upon setting a call, it is essentially requested to be assigned an IP address matched with the telephone number so as to enable the call setting.

So, upon setting the call, the transmitting side terminal 50 should request the server 20 to transmit the IP address matched with the telephone number. Thus, the server 20 manages the IP addresses matched with the telephone numbers in a database 70, and allows the directory module 224 to provide corresponding information if the transmitting side terminal 50 requests the IP address.

Also, the directory module 224 requests the server 20 to register the terminals 50 using regulated information so as to grasp the position of the terminal 50 in conjunction with the registration module 222. The server 20 updates, adds and deletes the information of the terminals 50 in the database 70.

Fifth, the gateway module 26 transforms signal, voice and fax data in a proper format between the networks so that the terminals 50 of the unified wireless communication system for the private network having the IP-based network can access to the PSTN for the connection with an outer user.

Next, the working maintenance module 24 of the server 20 includes: a system error managing module 241 for collecting a general error state of the system, such as an error processing of a hardware device of the system and an error processing depending on a usable call resource for the traffic service in order to guarantee a smooth service of the terminals 50 on service, and reporting the error state in real time; an operator matching module 242 for providing the operator with conveniences for the management, maintenance and repair with respect to various functions for devices and network management of the system; a performance managing module 243 for reporting a collection of reliable raw data with respect to an element affecting decision of the performance, and a statistical data for evaluating the system performance using the collected data; a constitution managing module 244 for making flexible the constitution of the system depending on the characteristic of a site to which the system is applied, and extending the system or enhancing the service quality; an authenticating module 245 for performing an authentication for a subscriber who uses an authentication method in the wireless environment together with a user authentication method used in an SIP; and a charge processing module 246 for collecting data with respect to use charge of the network and estimating the charge depending on use frequency of the network.

Hereinafter, elements of the working maintenance module 24 are concretely described.

First, as shown in Fig. 2, the system error managing module 241 collects a general error state of the system, such as an error processing of a hardware device of the system and an error processing depending on a usable call resource for the traffic service in order to guarantee a smooth service of the terminals 50 on service in the unified wireless communication system for the private network operating in a wired and wireless compositely coupled structure, and reports the kind and position of the error generated in a GUI (Graphic Use Interface 80) format, a text format and an audible alarm format to the operator in real time, thereby restoring the system error in early stages and thus minimizing the off-line sate time of the system.

Also, the system error managing module 241 keeps information about the generated error in the system during a constant time to provide a history management and inquiry function of the error and an inquiry function of various devices and operating state in the currently operating the unified wireless communication system for the private network by a command of the operator 70 or the GUI 80, thereby enabling the inquiry of the system state and instantaneous state.

Second, the operator matching module 242 provides the operator with the convenience for the management, maintenance and repair with respect to the system devices for providing voice/image/data communications services and various functions for the network management in the unified wireless communication system for the private network.

The operator matching module has a command processing function for processing a command by an input of a text format or an input through selection of a menu, a display function for expressing the system error, alarm and state using a graphic, and at the same time outputting a message to transmit the outputted message to the operator 70, a history function for storing and managing a history on the message outputted with respect to the system control and operation state, a managing range limiting function for limiting a managing range of the operator 70 every grade, and other additive service functions. Third, the performance managing module 243 collects reliable raw data with respect to an element affecting decision of the performance, and reports a statistical data for evaluating the system performance using the collected data to the operator.

The collected information for evaluating the system performance includes a general call processing statistics of the system, a call processing statistics every cell, a call processing statistics every kind of the terminals, a statistics of the wireless link and a statistics of the system error. In other words, the unified wireless communication system for the private network is a system for providing subscribers with voice/image/data communications services in the wireless/wired environment, and needs a periodic data collection about a number of network performance deciding factors so as to provide the subscribers connected to the network with smooth services, a new network design using performance data of the system provided according to a series of decided verification procedures, and a series of works such as addition of devices followed by the network maintenance and repair, and the network extension. To this end, the unified wireless communication system for the private network carries out a function that collects reliable raw data with respect to an element affecting decision of the performance, and reports a statistical data for evaluating the system performance using the collected data to the operator, through the performance managing module.

Fourth, the constitution managing module 244 makes flexible the constitution of the system depending on the characteristic of a site to which the system is applied, and extends the system or enhances the service quality.

Specifically, the constitution managing module 244 carries out a cell addition and deletion function, a parameters alteration function of the wireless connection module 40, such as cell frequency alteration, cell authentication processing data alteration, cell IP address alteration and the like, and an operation parameters alteration function of devices used in the system in conjunction with the call processing module 22 and a element of the working maintaining module 24, to thereby enhance the system performance. Further, the constitution managing module 244 provides the continuity of the system by carrying out the aforementioned functions under on-line circumstance of the system. Fifth, the authenticating module 245 performs authentications for subscribers who use an authentication method in the wireless environment together with a user authentication method used in the SIP such that the subscriber who must be supplied voice/image/data communications services, is provided services discriminated from non-approved subscribers. First authentication method performed by the wireless connection module 40 includes a method using the network name of the wireless LAN, a method for managing and processing a subscriber terminal information for deciding whether or not an access to the wireless connection module 40 is possible, and a method through the encryption using 40/128 bit WEP (Wired Equivalent Privacy). Second authentication method uses a user ID and a password of a terminal upon registering using the SIP used for processing signals between the terminal and the server 20.

Sixth, since the charge processing module 246 provides voice and data services by installing the unified wireless communication system for the private network at one business field and a plurality of business fields, it collects data with respect to usage charge of the network and calculates the charge depending on use frequency of the network.

Specifically, the charge processing module 246 collects a use time information from a connection setting to a connecting release, calculates the usage charge decided according to kinds of each set calls, stores and manages the charge data every group or every person, and provides the operator with data about the network usage charge at a decided time. Also, the charge processing module 246 collects information including kinds and usage time of calls used by respective users, and provides the collected information.

Fig. 7 is a flow chart for illustrating a voice call flow of the unified wireless communication system and the server for the private network in accordance with the present invention.

First, there is described a signal processing path for a call processing, such as the call setting or call release in the unified wireless communication system for the private network.

In case of the outer voice call communication, the signal processing has a path of the terminal 50 <-> the wireless connection module 40 <-> the switching module 30 <-> the server 20 <-> the PSTN.

In case of the inner voice call communication, the signal processing has a path of the terminal 50 <-> the wireless connection module 40 <-> the switching module 30 <-> the server 20 <-> the wireless connection module 40 <-> the terminal 50. Thus, the call processing has a common path of the terminal 50 <-> the wireless connection module 40 <-> the switching module 30 <-> the server 20. Meanwhile, in case of the outer Internet communication, a communication path between the inner terminals 50 is via the terminal 50 <-> the wireless cormection module 40 <-> the switching module 30 <-> the server 20 <-> the routing module 10 <-> the PSDN. Also, in case of the inner Internet communication, a communication path between the inner terminals 50 is via the terminal 50 <-> the wireless connection module 40 <-> the switching module 30 <-> the wireless connection module 40 <-> the terminal 50.

Further, in case of the outer voice call communication, the signal processing has a path of the terminal 50 <-> the wireless connection module 40 <-> the switching part 30 <-> the server 20 <-> the PSTN.

Moreover, in case of the inner voice call/image communication, the signal processing has a path of the terminal 50 <-> the wireless connection module 40 <-> the switching module 30 <-> the wireless connection module 40 <-> the terminal 50. Thus, the terminal 50 has a common call path of the terminal 50 <-> the wireless connection module 40 <-> the switching module 30.

Hereinafter, there is described a setting procedure of a call processing between the terminals with reference to the annexed Fig. 7a.

This call processing is carried out after the registration procedure is completed. As shown in Fig. 7a, the sender terminal 50 transmits 'INVITE' for the call setting to the server so as to try to send a call. (Fl) The server 20, which has received the 'INVITE' confirms the directory module and transmits the 'INVITE' to an IP address corresponding to an extension number of the receiver. (F2) The receiver terminal 50, which has received the 'INVITE' transmits to the server 20 a ringing signal representing both of the receivable state and the connecting state. (F3) Then, the server 20 transmits the ringing signal to the sender terminal 50. (F4) The receiver terminal 50 transmits a signal of 'ACCEPT' to the server 20 as an acknowledgement to the 'INVITE'. (F5) The server 20, which has received the signal of 'ACCEPT', transmits the signal of 'ACCEPT' to the sender terminal 50. (F6) The sender terminal 50, which has received the signal of 'ACCEPT' transmit an affirmative acknowledgement signal of ' ACK' to the server 20 (F7), and the server 20 transmits the signal of 'ACK' to the receiver terminal 50, so that a communication path is connected and thus a communication state is formed. (F8)

Thus, a communication path setting having a three-way handshaking of "INVITE, ACCEPT, and ACK" by the SIP protocol is completed between the sender terminal 50 and the receiver terminal 50.

While a communication service is connected by transmitting and receiving voice packets through the set communication path, if the voice packets are not received during a constant period, or normally ended, the communication between the sender terminal 50 and the receiver terminal 50 is released through a message of 'BYE' (F9), transmit and receives an OK signal of a call release report to the server 20, and is ended. (F10)

Next, there is described a procedure for setting a call processing between the terminal and the PSTN with reference to the annexed Fig. 7b.

The terminal 50 performs this call processing procedure after the registration procedure is completed, and is generally called 'sender signal'.

In other words, it is the call processing procedure in which the wireless terminal 50 that is the terminal 50 of the unified wireless communication system for the private network communicates with a phone subscriber connected to the PSTN.

In order to try a sending from the private terminal 50 to a subscriber of the PSTN, the private terminal 50 tries 'INVITE" to the server 20. (Fl) The server 20, which has received 'INVITE' from the private terminal 50 transmits to the PSTN a DTMF signal with respect to a phone number of the subscriber of the PSTN, requested by the private terminal 50. (F2) Thereafter, the PSTN carries out the phone connection with the phone number of the subscriber requested by the server 20, and transmits ringing signal to the server 20. (F3)

The server 20 transmits a ringback tone signal to the private terminal 50. (F4) In case that the subscriber of the PSTN answers the telephone, a connection signal is transmitted to the server 20 (F5), and the server 20 transmits the OK signal of the connection signal to the private terminal 50. (F6) Afterwards, if the private terminal 50 transmits an affirmative acknowledgement signal of "ACK' to the server 20 (F7), the server 20 transmits the connection signal of 'ACK' to the PSTN, thereby forming a communication path. (F8)

By the above procedure, the call connection setting between the private terminal 50 and the PSTN is completed, the communication path is formed, and thus voice packets are transmitted and received. Thereafter, if the private terminal 50 transmits the call ending signal of 'BYE' to the server 20 (F9), the server 20 transmits the OK signal to the private terminal 50 as the acknowledgement of the call signal, and releases the inner comiection. (F9) The server 20 transmits the release signal to the PSTN (F10), and the PSTN transmits a release completion signal in response to the release, thereby ending the connection of the PSTN. (Fl l)

Next, there is described a setting procedure between the PSTN and the private terminal with reference to the annexed Fig. 7c.

This call processing procedure is performed after the registration procedure is completed, and is generally called 'receiver signal' from a viewpoint of the private terminal 50.

If the server 20 receives a ringing signal tried by the PSTN (Fl), the server 20 transmits a connection signal acknowledging a setting of a communication path. (F2) Also, the server 20 outputs to the PSTN terminal a guidance comment requesting an extension number which wishes to communicate with. (F3)

After the server 20 detects the DTMF signal inputted from a subscriber of the PSTN (F4), it retrieves an IP address corresponding to the extension line number from the directory module. (F5) Afterwards, the server transmits the 'INVITE' to the private terminal 50 corresponding to the IP address. The private terminal 50, which has received the 'INVITE', transmits the ringing signal as a response signal to the 'INVITE' to the server 20. (F7) Then, the server 20 outputs a ringback tone to the subscriber of the PSTN. (F8) Thereafter, if the private terminal 50 responds to the ringing signal, the response signal (OK) is transmitted to the server 20. (F9) Then, the server 20 transmits the response signal to the private terminal 50, thereby advising that the call connection setting is completed. (F10)

By the above procedures, the call connection setting between the subscriber of the PSTN and the private terminal 50 is completed, the communication path is formed, and thus voice packets are transmitted and received.

Thereafter, if the subscriber of the PSTN transmits the call ending signal to the server 20 (Fl l), the server 20 transmits the release completion signal to the PSTN. (F12) If the server 20 transmits the call ending signal to the private terminal 50 (F13), the private terminal 50 transmits a response signal corresponding to the call ending signal, so that the call connection setting is released. (F14)

Meanwhile, since the unified wireless communication system for the private network provides services in the wireless environment, it should provide the continuity of the services with respect to the mobility of the private terminal 50. Accordingly, the unified wireless communication system for the private network provides a handoff function in which the voice communication service and the data service are possible without a stop of the services although a service area of the wireless connection module 40 for the connection of the terminal 50 is changed.

An environment for performing the handoff is serviceable by the user terminal tuning pilot from the respective wireless connection modules 40 and control parameters necessary for the wireless environment.

The unified wireless communication system for the private network performs the handoff function in a wireless period of a data link class that is class 2 of the OSI standards according to IEEE 802.11 series standards between the wireless connection part 40 and the terminal 50 provided with a device for performing the wireless interface. The handoff in the wireless LAN environment is carried out by a method in which the terminal 50 checks out the intensities of the received pilots of the multiple wireless connection modules 40, acquires the wireless connection module 40 having a strong pilot intensity, checks out a limitation value of the pilot intensity for the handoff decided in a MAC subclass of the class 2 of the wireless device equipped in the terminal, and the pilot intensity of the wireless connection modules 40 on the movement of the terminal 50, and if the pilot intensity arrives at the limitation value, the terminal 50 transits the service state into the wireless connection module 40 having the strongest pilot intensity.

When the terminal, which is using voice/data/image communications services, is moved to the neighboring wireless connection module 40 beyond the currently serviceable wireless connection area, the system structure needs to maintain the previously connected setting so as to prevent the using service from being cut off. Accordingly, in order to maintain the previously connected setting in the structure of the unified wireless communication system for the private network, in addition to an application for processing voice/image/data communications, there is requested a work for watching a connection state between the terminal 50 and the wireless connection part 40. This work senses a movement to the new wireless connection module 40, and transmits and acknowledges a registration request signal about a change in the service area to the server at that time. In this procedure, the switching module serving as an intermediate bridge updates the MAC (Media Access Control) address of the class 2 of the terminal for performing the handoff with respect to the corresponding port using a message transmitted to the server 20, so that the handoff in which a communication path of the terminal 50 <-> the wireless connection module 40 <-> the switching module 30 is successively connected is performed without a cutting.

Industrial Applicability

As described previously, the unified wireless communication system for the private network in accordance with the present invention has a structure variable with the network size, and solves the problem in that the service provider has to establish a vast service network for the services of telephone/image/data. Also, since it is possible to provide a user who wishes to use an IP telephone services with the service by establishing LAN, there are advantages in that the establishment of the network is easy and the installment costs are saved.

Also, since the conventional system has a structure in which the data network is separated from the telephone network, it is difficult to extend the network and carry out the maintenance and repair. However, since the system of the invention has a structure in which the voice network and the data network are integrated with each other, it is relatively easy to extend the network and carry out the maintenance and repair.

Further, the conventional network is made in a complicated wired connection structure. Since the conventional network cannot provide the mobility with respect to the user, and needs a further wired installation work according to the extension, separate installation cost and period are necessary. Whereas the network system of the invention provides a subscriber who accesses to the voice, image and data network, with a service based on the wireless LAN regulated in IEEE 802.11 series, the subscriber can use the services with the mobility within a serviceable area. In other words, a spatial effect is provided. Also, since the network is connected by the wireless communication, although the user is added or the network is altered, separate installation work and time are not necessary, e.g., spatial and time effects are obtained.

Furthermore, since the communication system of the invention is realized by using an Internet telephone protocol provided by IETF for the telephone service, it is flexibly accessible to a VoIP network when the current network is converted into the VoIP network in the future, and can be easily moved in combination with other network.

Moreover, the conventional communication system currently utilizes the desktop PC, the .notebook PC, etc., only for office and development, but the communication system of the invention can utilize them as a software IP phone for performing a voice processing, and thus provides inner and outer call services, to thereby extend the use of the terminal, solve a cost problem and a difficulty in the installing technology due to a dual installation of the PC and the telephone, thus provide economical and time gain with the users.

Also, small businesses adopting the conventional web server and mail server, need a burden of costs for the device installation and the server management in addition to the devices costs for the voice communication. However, since it is possible for the server 20 of the communication system of the invention to provide a service include the web server and mail server functions depending on the user's request condition. Thus, by integrating the inner network management, the subscriber management, and the additional services as a single network, the costs are saved and easy maintenance and repair are also possible. Further, in case of business fields in which businesses of the same characteristic are carried out, or a region in which frequent callings within the same area are generated, LAN is established by physically connecting the devices of the communication system of the invention in a proper format, and thus the service is provided, thereby enhancing the service quality followed by an independent network formation and management, and saving the service usage charge.

Furthermore, by lastingly extending the connection between the devices of the unified wireless communication system for the private network, there are obtained effect in that the network efficiency is enhanced as a whole due to the comiection with the previously installed networks, the network management is simplified, and the communication quality is enhanced, so that it becomes easy to establish the national organization communication network, low costs and high quality services are provided, and it affects on the development of the national communication service industries.

Moreover, since the unified wireless communication system for the private network supports all services of voice/image/data transmissions, it can be easily moved in combination with the wireless image communication anticipated in the IMT-2000, so that unlimited services can be provided to the users.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions can be made without departing from the scope and spirit of the invention as defined in the accompanying claims.

Claims

Claims:

1. A unified wireless communication system for a private network, comprising: a plurality of terminals for providing a user with voice, image and data communication services; a plurality of wireless connection modules wireless-connected with the plurality of terminals; a switching module for switching the plurality of wireless connection modules so as to receive and transmit data inputted and outputted through a public switching data network (PSDN) and a public switching telephone network (PSTN) from and to the plurality of terminals; a routing module for accessing to the Internet through the PSDN; and a server for providing a call processing for inner and outer voice communications through the PSTN and the PSDN, a data transmitting/receiving processing, a maintaining and repairing processing and a usage convenience for an operator.

2. The unified wireless communication system of claim 1, wherein the terminals comprise a desktop PC provided with a wireless LAN card of IEEE 802.11 series standards, a notebook, a PDA, a wireless terminal.

3. The unified wireless communication system of claim 1, wherein the server comprises: a call processing module for performing an inner VoIP call access and a call access to the PSTN; a gateway module for processing voice data transmission and receipt between the PSTN and the terminals; and a working maintaining module for maintaining and repairing a device constituting the unified wireless communication system, and for providing the operator with the convenience.

4. The unified wireless commumcation system of claim of 3, wherein the call processing module comprises: a call control module for performing call setting and releasing functions for the inner and outer voice communications, and the data communication of the terminals; a registration module for performing a subscriber registration; a data transmitting module for transmitting and receiving voice and fax data through a connection set with an outside; a directory service module for performing a conversion of an IP address and a phone number for a telephone service in an IP environment; and a gateway module for performing a telephone access and a data processing between the terminals having the wireless IP network environment and the subscriber of the PSTN.

5. The unified wireless communication system of claim 4, wherein the call control module performs a call setting by an SIP protocol and a three-way handshaking.

6. The unified wireless communication system of claim 4, wherein the registration module supports a method for storing the terminals' information by the operator, and a method for updating data to be matched with an SIP protocol when powers of the terminals are turned on/off in case that an area specified for a service is changed.

7. The unified wireless communication system of claim 4, wherein the data transmitting module performs an RTP protocol and an RTCP protocol.

8. The unified wireless communication system of claim 4, wherein the working maintaining module comprises: a system error managing module for collecting a general error state of the system, including an error processing for a hardware device constituting the system, and an error processing depending on a usable call resource state for the communication service so as to guarantee a smooth service of the terminal on service; an operator matching module for providing the operator with the convenience for the management, maintenance and repair with respect to various functions for devices and network management of the system; a performance managing module for reporting a collection of a reliable raw data with respect to an element affecting decision of the performance, and a statistical data for evaluating the system performance using the collected data; a constitution managing module for making flexible the constitution of the system depending on the characteristic of a site to which the system is applied, and extending the system or enhancing the service quality; an authenticating module for performing an authentication for a subscriber who uses an authentication method in the wireless environment together with a user authentication method used in an SIP; and a charge processing module for collecting data with respect to use charge of the network and estimating the charge depending on use frequency of the network.

9. The unified wireless communication system of claim 8, wherein the system error managing module reports kinds and positions of occurrence errors in a format of a GUI, a text and an audible alarm.

10. The unified wireless communication system of claim 8, wherein the operator matching module has a command processing function for processing a command by an input of a text format or an input through selection of a menu, a display function for expressing the system error, alarm and state using a graphic, and at the same time outputting a message to transmit the outputted message to the operator, a history function for storing and managing a history on the message outputted with respect to the system control and operation state, a managing range limiting function for limiting a managing range of the operator every grade, and other additive service functions.

11. The unified wireless communication system of claim 8, wherein the performance managing module performs a function for reporting the collection of the reliable raw data with respect to the element affecting the decision of the performance, and a statistical data for evaluating the system performance using the collected data to the operator.

12. The unified wireless communication system of claim 11, wherein the statistical data comprise a general call processing statistics of the system, a call processing statistics every cell, a call processing statistics every kind of the terminals, a statistics of the wireless link and a statistics of the system error.

13. The unified wireless communication system of claim 8, wherein the constitution managing module further a cell adding and deleting function, a cell frequency changing function, a cell authentication processing data transforming function, and a cell IP address changing function.

14. The unified wireless communication system of claim 8, wherein the charge processing module further comprises a function for collecting a use time information from a connection setting to a connecting release, the use time information corresponding to a time for which an external calling is connected.

15. The unified wireless communication system of claim 1, wherein the wireless connection module is an ISM band that is a non-approved frequency band based on IEEE 802.11 series standards.

16. The unified wireless communication system of claim 1 or 3, wherein the wireless connection module is a wireless LAN way and is a wireless technology in a

DSSS way.

17. The unified wireless communication system of claim 1, wherein an interface for a control signal between the wireless connection module and the server is a SNMP having an IETF RFC 1157 standards.

18. The unified wireless communication system of claim 1, wherein an interface standard between the wireless connection module and the switching module, and between the server and the routing module is an IEEE 802.3 Ethernet standard.

19. The unified wireless communication system of claim 1, wherein an interface between the terminals or between the terminals and the server, comprises: a control interface module for performing a call processing; a voice processing interface module for processing a voice data between the private terminals and subscribers of the public switching telephone network; and a voice signal processing interface module for a voice communication between the private terminals.

20. The unified wireless communication system of claim 19, wherein the control interface module is a SIP having the IETF RFC 2543 standards.

21. The unified wireless communication system of claim 19, wherein the voice processing interface module comprises a real-time protocol (RTP) of the IETF RFC 1889-1990 standards and a real-time control protocol (RTCP).

22. The unified wireless communication system of claim 19, wherein the voice signal processing interface module is a G.711 recommended by ITU-T, which PCM-decodes a voice frequency signal using a waveform coding technology.

23. The unified wireless communication system of claim 22, wherein the voice signal processing interface module further adopts a G.729 Annex A voice encoding way recommended by the ITU-T.

24. The unified wireless communication system of claim 1, wherein an interface between the private terminals and the public switching telephone network comprises: a signal interface module for processing voice or data signal between the private terminals and the public switching telephone network; and a voice/data interface module for transmitting and receiving the voice and data between the private terminals and the public switching telephone network.

25. The unified wireless communication system of claim 24, wherein the signal interface module has a DTMF signalling way.

26. The unified wireless communication system of claim 24, wherein the signal interface module an R2MF signal way for an El trunk.

27. The unified wireless communication system of claim 24, wherein the voice/data interface module for PCM-decoding a voice frequency signal using a technology for displaying the voice signal as a digital signal through quantization in a time axis using the waveform coding technology and a pulse size quantization.

28. The unified wireless communication system of claim 1, wherein when the terminal on service under a wireless LAN environment is moved to another service area beyond a corresponding service area, an information changed in the terminal is transmitted to the server for continuity of the service, and a communication path between the terminal and the switching module is reset to thereby perform a handoff.