KR20040022375A - System and Method for Wired/Wireless Call Exchanging and Dual-Channel Wireless Terminal Therefor - Google Patents

Abstract

PURPOSE: A wire/wireless call conversion system is provided to connect an attempted call to a PSTN via a public telephone line and a call conversion gateway, and to convert a call attempt of a wireless network into a wire network, thereby reducing call charges. CONSTITUTION: A dual channel wireless terminal(10) is converted into the first mode and the second mode, and performs wireless communication in different frequency bands according to each of the modes. A call conversion gateway(20) is connected with many public telephone lines, communicates with a PSTN(40), and wirelessly communicates with the dual channel wireless terminal(10) within a designated range if the dual channel wireless terminal(10) is converted into the second mode. If the dual channel wireless terminal(10) attempts a call by being converted into the second mode, the call conversion gateway(20) selects one of the public telephone lines, and attempts the call through the PSTN(40). The PSTN(40) receives state information of the dual channel wireless terminal(10) from the call conversion gateway(20), and transmits a reception attempt to the call conversion gateway(20) where the dual channel wireless terminal(10) is included, if the reception attempt is carried out through a line telephone(80) to the dual channel wireless terminal(10).

Description

System and Method for Wired / Wireless Call Exchanging and Dual-Channel Wireless Terminal Therefor}

The present invention relates to a call switching system between a wired communication network and a wireless communication network. More specifically, a wired / wireless call switching system and method for converting a call attempt on a wireless communication network into a wired communication network using a public telephone line, and a dual channel radio for the same It relates to a terminal.

With the expansion and widespread use of wireless terminals, the popularity of wireless terminals has increased in recent years so as to possess wireless terminals regardless of gender or age. With the spread of wireless terminals, it is possible to make a call with the desired counterpart and obtain desired information anytime and anywhere, but despite the high penetration rate of these wireless terminals, communication service usage fees are high and users are dissatisfied.

In addition, with the spread of wireless terminals, the utilization rate of public telephones installed in various places of the streets has decreased significantly. Public telephones have a disadvantage that they do not have mobility, which is the greatest advantage of wireless terminals, although call rates are cheaper and superior call quality than wireless terminals. Accordingly, resources such as waste of lines used for public telephones are wasted, and there is a problem that the balance between profits and maintenance / maintenance costs does not match.

On the other hand, according to the development process, the mobile communication system is the first generation of the analog frequency division multiple access method, the digital time division multiple access method and the second generation code division multiple access method, and the local and voice of the existing mobile communication service while ensuring the mobility of the terminal. It is divided into 3G, a mobile broadband system that can overcome the limitations of the central service and provide complete multimedia services. Comparing the 3rd generation mobile communication system with the existing mobile communication system, the IMT-2000 uses 2GHz, a worldwide common frequency band allocated by the ITU for global roaming. The frequency bandwidth per channel that determines the data transmission rate is 1.23MHz for digital mobile phones and PCS that use the same technology in Korea, whereas IMT-2000 can transmit voice, data and video as well as 2Mbps. Second-generation mobile telecommunications services will be gradually developed or absorbed into third generations, but fixed-line telecommunications services will evolve while maintaining complementary relationships with IMT-2000.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a wired / wireless call switching system and method that can reduce call charges by converting a call attempt by a wireless terminal into a wired network using a public telephone adjacent to the wireless terminal. There are technical challenges.

In addition, the present invention is equipped with a 900MHz band wireless transmission and reception module having excellent radio wave quality and characteristics in a wireless terminal, and attempts to make a call by switching to a frequency band with a 900 MHz frequency band according to a user's request to establish a neighboring public telephone line. There is a technical problem to provide a dual channel wireless terminal that can be switched to the wired network.

In addition, in the present invention, when the user switches the communication module of the wireless terminal to 900MHz to perform a call, and the user is currently trying to leave the 900MHz communication area, the call is not switched by routing the call path to the adjacent communication area. Keep your services available.

1 is an exemplary diagram of a communication network to which a wired / wireless call switching system according to the present invention is applied;

FIG. 2 is a detailed configuration diagram of the wired / wireless call switching gateway shown in FIG. 1;

3 is a detailed configuration diagram of a dual channel wireless terminal according to the present invention;

4 is a flowchart illustrating a wired / wireless call switching method according to an embodiment of the present invention;

5 is a flowchart illustrating a wired / wireless call switching method according to another embodiment of the present invention;

6 is another exemplary diagram of a communication network to which a wired / wireless call switching system according to the present invention is applied;

FIG. 7 is a detailed configuration diagram of the gateway exchange shown in FIG. 6;

8 is a flowchart illustrating a wired / wireless call switching method according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: dual channel wireless terminal 20: call switching gateway

30, 300-1 to 300-n: public telephone group 30-1 to 30-n: public telephone

40: public telephone switching network 50: wireless communication system

60: base station 70: wireless terminal

80: landline telephone 100: control unit

102 storage means 104 channel switching means

106: key input means 108: first communication network interface

110: second communication network interface 112: first communication module

114: second communication module 116: key pad portion

118: display unit 200: public telephone management means

202: location information transmission means 204: public telephone selection means

206: wired and wireless call exchange means 208: wired and wireless call exchange means

210: power detection means 212: alarm sound transmitting means

214: charging means 216: network interface

220: control unit 230: database

232: public telephone database 234: billing information database

400: gateway switch 402: controller

404: call transfer gateway management means

406: call switching gateway selection means 408: circuit selection request means

410: call routing means 412: communication network interface

414: Database

The present invention for achieving the above technical problem is switched to the first mode and the second mode is a dual-channel wireless terminal capable of wireless communication in different frequency bands according to each mode; It is connected to a plurality of public telephone lines by wire and can communicate with a public switched telephone network, and when the dual channel wireless terminal switches to the second mode, it can wirelessly communicate with the wireless terminal within a specified radius, and within the specified radius. A call switching gateway configured to select one of the public telephone lines so that the call attempt is made through a public switched telephone network when the dual channel wireless terminal switches to a second mode and attempts to make a call; And when the state information of the dual channel wireless terminal is received from the call switching gateway, and the call is received from the call switching gateway to the dual channel wireless terminal which is included in the communication range with the call switching gateway and is switched to the second mode, the incoming call is attempted. And a public switched telephone network for delivering an incoming call to the call transfer gateway including the dual channel wireless terminal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the following description, a dual channel wireless terminal includes a 900 MHz band communication module in a wireless terminal for transmitting and receiving voice and data through a wireless communication network such as a cellular phone, a PCS, a PDA, and has a function of switching a channel if necessary. One is a wireless terminal. Compared to PCS using the 1.8GHz band, 900MHz data communication has a long range of radio waves and has excellent transmittance and diffraction, so that there is less shadow area due to less environmental influences such as climate, buildings, and mountainous terrain. In the present embodiment, the case where the wireless terminal is equipped with a communication module of the 900MHz band has been described as an example, but may be changed to another frequency band according to the communication environment.

1 is a diagram illustrating a communication network to which a wired / wireless call switching gateway according to the present invention is applied.

As shown, the call divert gateway 20 of the present invention is wirelessly connected to the dual channel wireless terminal 10 in the 900 MHz frequency band, and includes a public telephone group including a plurality of public telephones 30-1 to 30-n. 30 is provided with an environment in which a wired connection is made. In addition, the dual channel wireless terminal 10 is generally equipped with an environment capable of communicating with the wireless communication system 50 through the base station 60 in the frequency band of the 800MHz or 1.8GHz band, the public telephone group 30 is It is connected to the public switched telephone network (PSTN) 40. Here, the wireless communication system 50 refers to a network operator that provides voice and data services wirelessly. Reference numeral 70 denotes a single channel wireless terminal 10 such as a cellular phone, PCS, PDA, etc., and reference numeral 80 denotes a wired telephone capable of attempting wired communication through the PSTN 40. .

The dual channel wireless terminal 10 may perform wired communication through a frequency band (for example, 800 MHz or 1.8 GHz band) capable of performing wireless communication through the wireless communication system 50 and the call transfer gateway 20. It is equipped with a communication module of a frequency band (for example, 900MHz), which can be configured as one module or divided into two modules. When the user of the dual channel wireless terminal 10 is present in an area (for example, within a radius of 2 km) within which the user can communicate with the call transfer gateway 20, the user of the dual channel wireless terminal 10 may set the terminal to the public telephone mode. And voice and data communication in a mode (hereinafter, referred to as a 'public telephone mode') that can communicate with the PSTN 40 through a public telephone (30-1 to 30-n) through a call transfer gateway (20). If the mobile station does not belong to an area capable of communicating with the call transfer gateway 20, the communication is switched to a mode capable of communicating with the wireless communication system 50 (hereinafter referred to as a wireless communication mode). Can be done. Here, the radius within which the propagation of the call transfer gateway 20 can reach can be further extended by adjusting the power output of the call transfer gateway 20.

In addition, the dual channel wireless terminal 10 registers in advance whether to use the call transfer service to a wired switch (not shown) of the PSTN 40, and periodically communicates with the call transfer gateway 20 to perform a call transfer gateway ( 20) and the wired switch of the PSTN 40 preferably periodically store which call transfer gateway 20 area they are currently in. Mode switching of the dual channel wireless terminal 10 is performed by a shortcut key. For example, when a user wants to switch a terminal in a wireless communication mode to a public telephone mode, a user may select a shortcut key preset in the dual channel wireless terminal 10. For example, you can switch the communication mode by pressing 900 *).

The call switching gateway 20 may be installed in plural to manage the public telephone group 30 at a predetermined distance, and when the user of the dual channel wireless terminal 10 attempts to call after switching the terminal to the public telephone mode, From the public telephone group 30, a communication line of the public telephones 30-1 to 30-n in the idle state is selected, and the dual channel wireless terminal 10-call switching gateway 20-public telephone 30-1. 30-n) -to establish a communication network leading to the PSTN 40.

On the other hand, when the user of the wired telephone 80 attempts to call the dual channel wireless terminal 10 within the communication radius of the call divert gateway 20, the wired switch of the PSTN 40 is located in the dual channel wireless terminal 10. Check call transfer gateway 20, and transmit a call attempt request signal to the corresponding call transfer gateway 20 to the outgoing landline telephone 80-public telephone 30-call transfer gateway 20-incoming dual channel wireless terminal (10) Call setting is made between the callers to reduce the call charges. In this case, the incoming dual channel wireless terminal 10 should be switched to the public telephone mode before the incoming call is attempted, and must perform location registration by continuous signal exchange with the call transfer gateway 20.

FIG. 2 is a detailed configuration diagram of the wired / wireless call switching gateway shown in FIG. 1.

As shown, the call transfer gateway 20 is a public telephone management means 200, location information transmission means 202, public telephone selection means 204, wired and wireless call exchange means 206, wired and wireless calls An exchange means 208, a power sensing means 210, an alarm sound transmitting means 212, a charging means 214, a communication network interface 216, a control unit 220 and a database 230. Here, the database 230 includes a public telephone DB 232 and billing information DB 234, these databases may be configured as one table, each may be configured as a separate table.

The public telephone management means 200 is a telephone number of each of a plurality of public telephones 30-1 to 30-n constituting the public telephone group 30 within a designated distance from the call transfer gateway 20, and the use state (calling). State or idle state) is stored and managed in the public telephone DB (232).

The location information transmitting means 202 continuously transmits and receives a signal with all the dual channel wireless terminals 10 included in the communication radius of the call switching gateway 20, and transmits the number and call switching gateway of the dual channel wireless terminal 10. The identification number of 20 is transmitted to the wired exchange of the PSTN 40 so that the wired exchange can recognize in which area the call transfer gateway 20 the dual channel wireless terminal 10 exists.

The public telephone selection means 204 is in an idle state of the public telephone group 30 belonging to the call transfer gateway 30 when the user of the dual channel wireless terminal 10 switches the call mode to the public telephone mode and attempts to make a call. One of the public telephones 30-1 to 30-n is selected. Call transfer gateway 20 stores all line numbers of public telephone groups 30-1 to 30-n of public telephone group 30 connected to itself in order of line numbers in public telephone DB 232. When a call is attempted from the dual channel wireless terminal 10 and an idle line is selected, the line number table is sequentially searched to select a line recognized as the first idle line.

The wire-free call exchange means 206 receives a call attempt from the dual channel wireless terminal 10 when the public telephone 30-1 to 30-n line is selected by the public telephone selection means 204. Through the public telephone line through the connection to the PSTN (40), it is possible to request the call setup from the wired switch to the calling terminal.

The wired-wireless call exchange means 208 is a PSTN (when a call is attempted from the wireline telephone 80 to the dual channel wireless terminal 10 which belongs to the communication radius of the call transfer gateway 20 and is switched to the public telephone mode. A call attempt request is received from 40 and a ring signal is transmitted to the dual channel wireless terminal 10.

The power sensing unit 210 detects the signal strength transmitted and received with all the dual channel wireless terminals 10 within the communication radius of the call switching gateway 20 so that the dual channel wireless terminal 10 detects the call switching gateway 20. Check if communication is possible.

In the case of the dual channel wireless terminal 10 which is within the communication radius of the call transfer gateway 20 and is in an idle state, when the transmit / receive power measured by the power sensing means 210 is equal to or less than a specified value, the corresponding dual channel wireless terminal 10 Even when switching to the public telephone mode, the call cannot be attempted through the call switching gateway 20, and the alarm sound transmitting means 212 informs the dual channel wireless terminal 10 so that the user can recognize it. . On the other hand, in the dual channel wireless terminal 10 which is within the communication radius of the call transfer gateway 20 and is busy, the alarm sound transmitting means 212 when the transmit / receive power detected by the power detecting means 210 is equal to or less than a specified value. By sending an alarm sound notifying that the call can be transferred to the dual channel wireless terminal 10, the user can be prepared for a sudden call change as well as not feel uncomfortable.

In addition, the power detecting unit 210 detects the signal strength transmitted from the dual channel wireless terminal 10 when the user inputs a designated shortcut and converts the dual channel wireless terminal 10 to the public telephone mode. If the signal is greater than or equal to the specified value, a response signal is transmitted to cause the dual channel wireless terminal 10 to switch to the public telephone mode, and if the received signal is less than or equal to the specified value, the public telephone is transmitted by the alarm sound transmitting means 212. The dual channel wireless terminal 10 is notified that it cannot switch to the mode. At this time, not only the alarm sound but also a message such as 'Not in service area' and 'Please wait' can be sent together.

As described above, the alarm sound transmitting unit 212 is capable of switching to the public telephone mode when the transmission / reception power is minute and the call cannot be attempted, and when the transmission / reception power is attenuated in a busy state and the call may be switched. When the signal strength of the wireless terminal 10 is less than or equal to the specified value, an alarm sound notifying the fact is transmitted to the dual channel wireless terminal 10. In addition, when another user wants to use the public telephone selected for the call of the dual channel wireless terminal 10, an alarm sound or a notification message such as 'in a call' may be transmitted.

The billing means 210 generates billing information according to the talk time of the user of the dual channel wireless terminal 10 and the used public telephone line information, and stores the billing information in the billing information DB 234 and stores the billing information stored in the PSTN 40. Send periodically. Accordingly, the communication fee through the dual channel wireless terminal 10 can be charged in addition to the service charge of the wireless communication system 50 without being charged and added to the wired telephone service charge. The communication network interface 212 is a means for performing wired and wireless communication with the dual channel wireless terminal 10 and the public telephone group 30 which have switched to the public telephone mode, and the control unit 220 performs the overall operation of each functional means described above. To control.

3 is a detailed block diagram of a dual channel wireless terminal according to the present invention.

As shown, the dual channel wireless terminal 10 includes a control unit 100, a storage unit 102, a channel switching unit 104, a key input unit 106, a first communication network interface 108, and a second communication network interface. 110, a first communication module 112, a second communication module 114, a keypad unit 116, and a display unit 118.

The channel switching means 104 is used when the user of the dual channel wireless terminal 10 inputs a switching command for selecting one of the wireless communication mode and the public telephone mode to the input means 106 by operating the keypad unit 116. Accordingly, the communication mode of the dual channel wireless terminal 10 is switched to either the wireless communication mode or the public telephone mode. In this case, it is preferable to display the current mode and the transmission / reception state of the dual channel wireless terminal 10 on the display unit 118. For example, if a user enters a shortcut key to switch to payphone mode, the user displays the current status of the device by displaying a message such as Switch to payphone mode, please wait, or not in service area. To know. The message related to the service switching may be stored in the storage unit 102 of the dual channel wireless terminal 10 and displayed by selecting and displaying a message matching the current situation or being received from the call switching gateway 20.

The first communication network interface 108 activates the first communication module 112 to communicate with the wireless communication system 50 through the base station 60 when the dual channel wireless terminal 10 switches to the wireless communication mode. When the dual channel wireless terminal 10 switches to the public telephone mode, the second communication network interface 110 activates the second communication module 114 to perform the PSTN (through the public telephones 30-1 to 30-N). To communicate with 40). Reference numeral 100 denotes a control unit. In the case of configuring two communication modules in this way, it is easy to extend the current commercially available wireless terminal to a dual channel wireless terminal.

4 is a flowchart illustrating a wired / wireless call switching method according to an embodiment of the present invention, which illustrates a case where a call is attempted by switching a dual channel wireless terminal to a public telephone mode.

As the user of the dual channel wireless terminal 10 belonging to the communication radius of the call transfer gateway 20 wants to change the communication mode by operating the keypad unit 116, the channel switching means 104 changes the communication mode to the public telephone. The channel is changed to switch to the mode (S101). In this case, it is preferable to display the channel change fact on the display unit 118. As such, after the communication mode of the dual channel wireless terminal 10 is switched to the public telephone mode, when a call is attempted by inputting a wired or wireless terminal number of a receiver to be called (S102), the dual channel wireless terminal 10 Communication between the call transfer gateway 20 and the call transfer gateway 20 becomes possible, and communication with the wireless communication system 40 becomes impossible. Therefore, the call attempt of the dual channel wireless terminal 10 is performed by the call transfer gateway (not the wireless communication system 50). 20).

At this time, the call transfer gateway 20 confirms the call charge payment history of the user of the dual channel wireless terminal 10 determined by the charging means 210 by referring to the charging information DB 234. It is preferable to check whether the user is a legitimate user (S103), and the public telephone selection means 204 refers to the public telephone DB 232 when the user of the corresponding dual channel wireless terminal 10 turns out to be a legitimate user. The telephone is selected (S104).

Thereafter, the wired call exchange means 206 of the call switching gateway transmits the call attempt request of the dual channel wireless terminal to the PSTN 40 through the selected public telephone (S105, S106), and accordingly the dual channel wireless terminal ( 10) and a call path is formed between the PSTN 40 (S107).

Although not shown, after a call path is formed between the dual channel wireless terminal 10 and the PSTN 40, the PSTN 40 checks the receiver information so that a ring signal is transmitted to the wired or wireless terminal of the corresponding receiver. In addition, the charging means 210 stores the talk time from the user of the dual channel wireless terminal 10 and the receiver to the end of the call in the charging information DB 236, so that the PSTN 40 and the wireless communication system (if necessary) 50).

In addition, after the step of forming the call path (S107), when the user of the dual channel wireless terminal 10 moves and the transmission / reception power with the call switching gateway 20 is sensed by the power detecting means 210 to the specified value or less, the alarm sound is transmitted. The means 212 may inform the dual channel wireless terminal 10 of this.

As described above, when the call is attempted by switching the dual channel wireless terminal 10 to the public telephone mode, it is not necessary to pass through the wireless communication system, thereby reducing the call charge.

5 is a flowchart illustrating a wired / wireless call switching method according to another embodiment of the present invention, and illustrates a case in which a wired terminal user attempts to make a call to the dual channel wireless terminal 10.

To this end, the user of the dual channel wireless terminal 10 should register the use of the service in the wired switchboard of the PSTN 40 and switch the dual channel wireless terminal 10 to the public telephone mode, and continuously with the call switching gateway 20. Location registration should be done by sending and receiving signals. In addition, the call transfer gateway 20 should periodically notify the wired switch to the state of the dual channel wireless terminal 10 included in its communication radius (S200).

When the caller using the wired terminal 80 attempts to call the dual channel wireless terminal 10 (S201), the wired exchange of the PSTN 40 extracts the receiver information so that the receiver can use the call transfer service. The call switching gateway 20 to which the corresponding dual channel wireless terminal 10 belongs is referred to by checking whether the user is a registered user (S202) and referring to the location information of the dual channel wireless terminal 10 transmitted from the location information transmitting means 202. Extract the identification number (S203).

Subsequently, the public telephones 30-1 to 30-n in the idle state are selected from the public telephone group 30 included in the corresponding call divert gateway 20 (S204), and the call divert gateway through the selected public telephone ( 20, the call attempt request and the call request number of the dual channel wireless terminal 10 are transmitted (S205). Accordingly, the wire-wireless call switching means 208 of the call switching gateway 20 generates a ring signal to the corresponding dual channel wireless terminal 10 (S206), and the dual channel wireless terminal 10 is connected to the ring signal. In response, a call path is formed between the caller terminal and the dual channel wireless terminal 10 (S207).

Even in this case, when the user of the dual channel wireless terminal 10 moves and the transmission / reception power with the call switching gateway 20 is detected by the power detection means 210 to be less than or equal to the specified value, the alarm sound transmitting means 212 may transmit the dual channel wireless signal. The terminal 10 may be notified.

According to the present embodiment, the call attempted by the caller to the dual channel wireless terminal 10 is directly received through the wired network without passing through the wireless network, thereby reducing the burden on the caller.

6 is another exemplary diagram of a communication network to which a wired / wireless call switching gateway according to the present invention is applied, that is, when a dual channel wireless terminal in which a call path is set through a call switching gateway is about to move out of a communication radius of a corresponding call switching gateway, When the transmit / receive power is attenuated below a specified value, a communication network configuration capable of routing a call to a public telephone line included in an adjacent other call switching gateway is shown.

As shown, the plurality of call divert gateways 20-1 to 20-n are wirelessly connected to the dual channel wireless terminal 10 within each communication radius in the 900 MHz frequency band, and each adjacent public telephone group ( 300-1 to 300-n) and a wired connection environment, and are connected to the gateway switch 400.

The gateway switch 400 manages information on each of the plurality of call transfer gateways 20-1 to 20-n, and uses a call path established with the current dual channel wireless terminal 10 according to a request of the call transfer gateway. It is responsible for routing to telephone lines. For example, when a dual channel wireless terminal 10 performing a call via a call transfer gateway attempts to leave the communication radius of the call transfer gateway, that is, when the transmit / receive power is detected to be less than or equal to the specified value, the call transfer gateway is used as a gateway switch. At 400, a call forwarding gateway is selected to request that the call be routed. Accordingly, the gateway switch 400 transmits the corresponding dual channel wireless terminal 10 information to a plurality of call transfer gateways adjacent to the current call transfer gateway to check the transmit / receive power, and selects the call transfer gateway having the largest transmit / receive power. Requires the selection of an idle public telephone line. Thereafter, as the call switching gateway selects the public telephone line, the communication channel with the dual channel wireless terminal 10 is routed to the call switching gateway so that the call can be maintained without interruption.

In the present embodiment, the functions of the dual channel wireless terminal 10, the call switching gateways 20-1 to 20-n, and the like are similar to or the same as those shown in Figs. .

FIG. 7 is a detailed block diagram of the gateway exchange shown in FIG.

The gateway switch 400 includes a control unit 402, call switching gateway management means 404, call switching gateway selecting means 406, circuit selection requesting means 408, call routing means 410, communication network interface 412 and Database 414.

The call divert gateway management means 404 stores and manages the identification number, location information, etc. of each call divert gateway 20-1 to 20-n in the database 414, and the call divert gateway selection means 406 When a routing request is received from the call switch gateways 20-1 to 20-n, the corresponding dual channel wireless terminal information is transmitted to a plurality of call transfer gateways adjacent to the call switch gateways 20-1 to 20-n requesting routing. It checks and transmits the transmission and reception power with the corresponding dual channel wireless terminal, and selects the call switching gateway having the maximum transmission and reception power.

The circuit selection requesting means 408 requests to select an idle line among public telephone lines belonging to the public telephone group connected to the call switching gateway selected by the call switching gateway selecting means 406, and the call routing means 410 If the call transfer gateway selected by the call transfer gateway selecting means 406 notifies that the idle air circuit is selected, the communication path of the call transfer gateway requesting routing is routed to the reselected call transfer gateway and the public telephone line accordingly.

8 is a flowchart illustrating a wired / wireless call switching method according to another embodiment of the present invention. In this embodiment, for convenience of description, the call switching gateway and the public telephone line to which the dual channel wireless terminal 10 is primarily connected are referred to as the first call switching gateway and the first public telephone line, and are reselected according to the transmission / reception power decrease. Call transfer gateways and public telephone lines will be referred to as second call transfer gateways and second public telephone lines.

First, in a state in which a call path is formed between the dual channel wireless terminal 10 and the called terminal by the procedure described with reference to FIG. 4 or 5 (S301), power detection means of the first call switching gateway is provided. The controller continually detects transmission / reception power with the dual channel wireless terminal 10 currently performing the call (S302).

If the dual channel wireless terminal moves or the transmit / receive power with the first call switching gateway is attenuated by a predetermined value or less due to an interference signal from the surroundings, the first call switching gateway requests routing to the gateway switch 400 ( S303). That is, when the transmit / receive power between the dual channel wireless terminal 10 and the first call switching gateway is reduced, the dual channel wireless terminal 10 determines that it is near a communication radius boundary of the first call switching gateway, It requires routing to an adjacent call transfer gateway. At this time, the first call transfer gateway preferably transmits the identification number of the first call transfer gateway and the identification number of the dual channel wireless terminal to the gateway exchange together.

The call switch gateway selecting means 406 of the gateway switch 400 that has received the routing request of the first call switch gateway, refers to the database 414 from the identification number of the first call switch gateway, and locates the location information of the first call switch gateway. And transmits information (identification number, etc.) of the dual channel wireless terminal 10 to a plurality of call switching gateways adjacent to each other to confirm transmission and reception power. Accordingly, when the transmission and reception power between the corresponding dual channel wireless terminals 10 is received from the plurality of call switching gateways, the call switching gateway having the maximum transmission and reception power is selected (S304). The circuit selection requesting means 408 requests to select the idle public telephone line to the selected second call transfer gateway (S305).

Accordingly, the public telephone selection means of the second call transfer gateway selects an idle public telephone line from the connected public telephone groups (S306), and notifies the gateway switch 400 of the result (S307). Accordingly, the call routing means 410 of the gateway switch 400 connects to the second public telephone line through the second call switching gateway (S308), and transmits routing information to the dual channel wireless terminal 10 (S309). ). That is, the connection information of the second call transfer system is transmitted to induce setting of a call. Accordingly, the call path is reset between the dual channel wireless terminal 10-the second call switching gateway-the second public telephone line-the called terminal (S310), and the user does not feel the call path reset and without changing the call path. It is possible to continue the call in the state (S311).

As such, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

As described above, the present invention includes a communication module capable of performing wireless communication in a 900 MHz band in a wireless terminal such as a cellular phone, a PCS, a PDA, and the like, and is capable of wireless communication in a 900 MHz band connected to a plurality of public telephones. When a gateway is installed and a call is attempted through a wireless communication function of 900 MHz band, the call attempt is connected to the PSTN via a call switching gateway and a public telephone line, and the call attempt of the wireless network is switched to a wired network. It can be reduced.

In addition, when a call is attempted from a wired terminal to a dual channel wireless terminal within the communication radius of the call switching gateway, the caller bears the call charge by allowing the caller to directly receive the call attempt request via the wired network without passing through the wireless communication system. The effect is to relieve.

In addition, by installing a gateway switch that manages the state of a plurality of call transfer gateway, it is possible to continue to use the service without switching the call even if the user moves to another call transfer gateway area during the call.

Claims (30)

A dual channel wireless terminal switched to the first mode and the second mode and capable of wireless communication in different frequency bands according to respective modes; And It is connected to a plurality of public telephone lines by wire and can communicate with a public switched telephone network, and when the dual channel wireless terminal switches to the second mode, it can wirelessly communicate with the wireless terminal within a specified radius, and within the specified radius. A call switching gateway configured to select one of the public telephone lines so that the call attempt is made through a public switched telephone network when the dual channel wireless terminal switches to a second mode and attempts to make a call; And Receiving state information of the dual channel wireless terminal from the call switching gateway, when an incoming call is attempted to a dual channel wireless terminal within a radius capable of communicating with the call switching gateway and switched to a second mode through a wired telephone. A public switched telephone network for transmitting an incoming call to the call transfer gateway including a dual channel wireless terminal; Wired and wireless call switching system having a. The method of claim 1, wherein the call transfer gateway is Public telephone management means for storing and managing a telephone number of each of a plurality of public telephones constituting said public telephone group within a designated distance from said call transfer gateway, and information on usage status in a database; Location information transmitting means for transmitting and storing the number of the wireless terminal capable of communicating with the call transfer gateway and the identification number of the call transfer gateway to the public switched telephone network; Public telephone selection means for selecting one public telephone in an idle state from the public telephone group as the wireless terminal user switches the call mode of the wireless terminal to the designated frequency band and attempts a call; And Wired / wireless call exchange means for causing a call attempt of the wireless terminal to be connected to the public switched telephone network through a public telephone selected by the public telephone selection means; Wired and wireless call switching system having a. The method of claim 2, wherein the call transfer gateway is Power sensing means for sensing the strength of transmission / reception power with the dual channel wireless terminal in an idle state or a call state included within a specified radius from the call transfer gateway; And If the transmission / reception power between the dual channel wireless terminal switched to the second mode and the call switching gateway is determined to be lower than or equal to the value specified by the power sensing means, and the call cannot be attempted, the dual channel wireless terminal is turned off in the second mode. If the transmission / reception power with the call switching gateway is reduced to a predetermined value or less as a result of the determination by the power sensing means in a call state, the signal strength of the dual channel wireless terminal to switch to the second mode is determined by the power sensing means. As a result, if less than a specified value, alarm sound transmitting means for generating an alarm sound in any one or more of the cases that other users want to use a public telephone corresponding to a public telephone line allocated for a call of the dual channel wireless terminal ; Wired and wireless call switching system further comprising. The method of claim 2, And the call transfer gateway further comprises a wired / wireless call exchange means for receiving the call attempt from the public switched telephone network and transmitting the incoming call to the wireless terminal when the incoming call is attempted to the wireless terminal. The method of claim 2, And the call transfer gateway further comprises charging means for generating charging information according to a talk time of the wireless terminal user in a database and periodically transmitting the stored charging information to a public switched telephone network. According to claim 1, And a center frequency of a second mode capable of wireless communication between the dual channel wireless terminal and the call switching gateway is 900 MHz. According to claim 1, The dual channel wireless terminal performs voice and data communication through a cellular wireless communication system and a base station in a first mode, and performs voice and data communication in a frequency band having a center frequency of 900 MHz with a call switching gateway in a second mode. Wired and wireless call transfer system. A dual channel wireless terminal switched to the first mode and the second mode and capable of wireless communication in different frequency bands according to respective modes; And It is connected to a plurality of public telephone lines by wire and can communicate with a public switched telephone network, and when the dual channel wireless terminal switches to the second mode, it can wirelessly communicate with the wireless terminal within a specified radius, and within the specified radius. A plurality of call divert gateways, when the dual channel wireless terminal is switched to a second mode and selects one of the public telephone lines so that the call attempt is made through a public switched telephone network; When the dual channel wireless terminal receives a routing request from the call switching gateway performing voice and / or data communication, the dual channel wireless terminal transmits the dual channel wireless terminal information to a plurality of gateways adjacent to the communicating call switching gateway, thereby transmitting the dual channel wireless terminal information. A gateway exchanger for verifying transmit / receive power with a channel wireless terminal, and receiving transmit / receive power from each of the plurality of adjacent call transfer gateways and routing a call path to a call transfer gateway having a maximum transmit / receive power; And Receiving state information of the dual channel wireless terminal from the call switching gateway, when an incoming call is attempted to a dual channel wireless terminal within a radius capable of communicating with the call switching gateway and switched to a second mode through a wired telephone. A public switched telephone network for transmitting an incoming call to the call transfer gateway including a dual channel wireless terminal; Wired and wireless call switching system having a. 9. The system of claim 8, wherein the gateway exchange is Call diversion gateway management means for storing and managing identification numbers and location information of the plurality of call diversion gateways in a database; When the routing request is received from the call switching gateway, the corresponding dual channel wireless terminal information is transmitted to a plurality of call switching gateways adjacent to the call switching gateway requesting the routing to check and transmit power to and from the dual channel wireless terminal. Call switching gateway selecting means for selecting a call switching gateway having a maximum transmit / receive power; Circuit selection requesting means for requesting a call switching gateway selected by the call switching gateway selecting means to select an idle line among public telephone lines belonging to the connected public telephone group; And When the call transfer gateway selected by the call transfer gateway selecting means notifies that the idle air circuit is selected, the call transfer gateway and the public telephone according to which the call channel of the dual channel wireless terminal connected to the call transfer gateway requesting routing is reselected. Call routing means for routing to the circuit Wired and wireless call switching system having a. 10. The system of claim 8, wherein the call divert gateway is Public telephone management means for storing and managing a telephone number of each of a plurality of public telephones constituting said public telephone group within a designated distance from said call transfer gateway, and information on usage status in a database; Location information transmitting means for transmitting and storing the number of the wireless terminal capable of communicating with the call transfer gateway and the identification number of the call transfer gateway to the public switched telephone network; Public telephone selection means for selecting one public telephone in an idle state from the public telephone group as the wireless terminal user switches the call mode of the wireless terminal to the designated frequency band and attempts a call; And Wired / wireless call exchange means for causing a call attempt of the wireless terminal to be connected to the public switched telephone network through a public telephone selected by the public telephone selection means; Wired and wireless call switching system having a. 11. The method of claim 10, wherein the call divert gateway is Power sensing means for sensing the strength of transmission / reception power with the dual channel wireless terminal in an idle state or a call state included within a specified radius from the call transfer gateway; And If the transmission / reception power between the dual channel wireless terminal switched to the second mode and the call switching gateway is determined to be lower than or equal to the value specified by the power sensing means, and the call cannot be attempted, the dual channel wireless terminal is turned off in the second mode. If the transmission / reception power with the call switching gateway is reduced to a predetermined value or less as a result of the determination by the power sensing means in a call state, the signal strength of the dual channel wireless terminal to switch to the second mode is determined by the power sensing means. As a result, if less than the specified value, alarm sound transmitting means for generating an alarm sound in any one of the cases that other users want to use the public telephone corresponding to the public telephone line allocated for the call of the dual channel wireless terminal ; Wired and wireless call switching system further comprising. The method of claim 10, And the call transfer gateway further comprises a wired / wireless call exchange means for receiving the call attempt from the public switched telephone network and transmitting the incoming call to the wireless terminal when the incoming call is attempted to the wireless terminal. The method of claim 10, And the call transfer gateway further comprises charging means for generating charging information according to a talk time of the wireless terminal user in a database and periodically transmitting the stored charging information to a public switched telephone network. The method of claim 8, And a center frequency of a second mode capable of wireless communication between the dual channel wireless terminal and the call switching gateway is 900 MHz. The method of claim 8, The dual channel wireless terminal performs voice and data communication through a cellular wireless communication system and a base station in a first mode, and performs voice and data communication in a frequency band having a center frequency of 900 MHz with the call transfer gateway in a second mode. Wired and wireless call transfer system. Connected to a public switched telephone network through a public telephone group including a plurality of public telephones, capable of wireless communication with a wireless terminal in a designated frequency band, and transmitting a call attempt of the wireless terminal to a public switched telephone network through the public telephone line; As a wired or wireless call transfer method in a call transfer system, Selecting one public telephone in an idle state of the public telephone group as the wireless terminal user switches the call mode of the wireless terminal to the designated frequency band and attempts a call by inputting a receiving terminal number; And Transmitting a call attempt request of the wireless terminal to the public switched telephone network through the selected public telephone to form a call path between the wireless terminal and the public switched telephone network; Wired and wireless call transfer method comprising a. The method of claim 16, And authenticating whether the wireless terminal user is a legitimate user after the wireless terminal user attempts to make a call and before selecting an idle public telephone. The method of claim 16, After the call path is formed between the wireless terminal and the public switched telephone network, the public telephone exchange network checks the receiver information and transmits a ring signal to the corresponding receiver terminal. When a call is started between the wireless terminal and the receiver terminal, And generating charging information according to a call time between a wireless terminal and a receiver terminal and transmitting the charging information to the public switched telephone network. The method of claim 16, The specified frequency band has a center frequency of 900MHz wired or wireless call switching method. The method of claim 16, The wireless terminal communicates with the wireless communication system through a base station and operates in two communication modes for performing data communication in a frequency band having a center frequency of 900 MHz. A call switching gateway connected to a public switched telephone network through a public telephone group including a plurality of public telephones, capable of wireless communication with a wireless terminal in a designated frequency band, and transmitting a call attempt of the wireless terminal through the public switched telephone network; A wired / wireless call transfer method in a call transfer system that includes Continuously transmitting the wireless terminal number and an identification number of a call transfer gateway to which the wireless terminal belongs to the public switched telephone network; Ascertaining the wireless terminal user information as a call is attempted from the calling terminal to the wireless terminal through the public switched telephone network; Extracting a call transfer gateway to which the wireless terminal belongs; Selecting one public telephone in an idle state among the public telephone groups included in the call transfer gateway; Sending a call attempt request of the wireless terminal to the call transfer gateway via the selected public telephone; And Transmitting a ring signal to the wireless terminal; Wired and wireless call transfer method comprising a. The method of claim 21, After transmitting a ring signal to the wireless terminal, when a call is initiated between the caller terminal and the wireless terminal, the charging information according to the call time between the caller terminal and the wireless terminal is generated to generate the billing information for the public switched telephone network operator and the wireless communication. Wired and wireless call transfer method further comprising the step of transmitting to the system operator. The method of claim 21, And the specified frequency band has a center frequency of 900 MHz. The method of claim 21, And the wireless terminal communicates with the wireless communication system through a base station and performs data communication with the call transfer gateway in a frequency band having a center frequency of 900 MHz. A wireless terminal connected to a wireless communication system through a base station and connected to a public switched telephone network through a public telephone, A first communication network interface capable of communicating with a wireless communication system by a first frequency band; A second communication network interface capable of wireless communication by a designated second frequency band excluding the first frequency band; And Channel switching means for selecting a communication mode using any one of the first frequency band and the second frequency band; Dual channel wireless terminal having a. The method of claim 25, The second frequency band is a dual channel wireless terminal having a center frequency of 900MHz. A dual channel wireless terminal capable of wireless communication in different frequency bands, connected to a public switched telephone network through a public telephone group including a plurality of public telephones, and capable of wireless communication with a wireless terminal in a designated frequency band, When a routing request is received from a plurality of call switching gateways and the call switching gateway for transmitting an attempt to the public switched telephone network through the public telephone line, transmission and reception power between the plurality of gateways adjacent to the call switching gateway and the dual channel wireless terminal. A wired / wireless call switching method in a call switching system including a gateway switch for routing a call path according to the present invention, Forming a call path between the dual channel wireless terminal and the called terminal; A first call transfer gateway continuously detecting transmit / receive power with the dual channel wireless terminal and requesting routing to the gateway exchange when the transmit / receive power is equal to or less than a specified value; Checking, by the gateway exchange, location information of the first call diversion gateway and requesting a plurality of adjacent call diversion gateways to confirm transmission and reception power with the dual channel wireless terminal; Selecting a second call transfer gateway having a maximum transmit / receive power when the transmit / receive power between the corresponding dual channel wireless terminals is received from a plurality of call transfer gateways adjacent to the first call transfer gateway; Requesting an idle public telephone line to be selected as the second call diversion gateway; As the second call divert gateway selects an idle public telephone line and notifies the gateway switch of the selection result, the gateway switch connects to the public telephone line through the second call diverted gateway, while routing to the dual channel wireless terminal. Transmitting information; And Resetting a call path between the dual channel wireless terminal, a second call transfer gateway, a public telephone line, and a called terminal; Wired and wireless call transfer method comprising a. The method of claim 27, The requesting routing of the first call transfer gateway to the gateway exchange further includes transmitting an identification number of the first call transfer gateway and an identification number of the dual channel wireless terminal. Way. 29. The method of claim 27, wherein forming a currency path Selecting one public telephone in an idle state of the public telephone group as the wireless terminal user switches the call mode of the wireless terminal to the designated frequency band and attempts a call by inputting a receiving terminal number; And Transmitting a call attempt request of the wireless terminal to the public switched telephone network through the selected public telephone to form a call path between the wireless terminal and the public switched telephone network; Wired and wireless call transfer method comprising a. 29. The method of claim 27, wherein forming a currency path Continuously transmitting the wireless terminal number and an identification number of a call transfer gateway to which the wireless terminal belongs to the public switched telephone network; Ascertaining the wireless terminal user information as a call is attempted from the calling terminal to the wireless terminal through the public switched telephone network; Extracting a call transfer gateway to which the wireless terminal belongs; Selecting one public telephone in an idle state among the public telephone groups included in the call transfer gateway; Sending a call attempt request of the wireless terminal to the call transfer gateway via the selected public telephone; And Transmitting a ring signal to the wireless terminal; Wired and wireless call transfer method comprising a.