WO2004023771A1 - System and method for wired/wireless call exchanging and dual-channel wireless terminal therefor - Google Patents

System and method for wired/wireless call exchanging and dual-channel wireless terminal therefor Download PDF

Info

Publication number
WO2004023771A1
WO2004023771A1 PCT/KR2003/001761 KR0301761W WO2004023771A1 WO 2004023771 A1 WO2004023771 A1 WO 2004023771A1 KR 0301761 W KR0301761 W KR 0301761W WO 2004023771 A1 WO2004023771 A1 WO 2004023771A1
Authority
WO
WIPO (PCT)
Prior art keywords
wireless terminal
call
call forwarding
dual
payphone
Prior art date
Application number
PCT/KR2003/001761
Other languages
French (fr)
Inventor
Seung-Jung Shin
Original Assignee
Mlml Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR10-2003-0021555A external-priority patent/KR100521989B1/en
Application filed by Mlml Co., Ltd. filed Critical Mlml Co., Ltd.
Priority to AU2003256123A priority Critical patent/AU2003256123A1/en
Publication of WO2004023771A1 publication Critical patent/WO2004023771A1/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/54—Arrangements for diverting calls for one subscriber to another predetermined subscriber
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M2203/00—Aspects of automatic or semi-automatic exchanges
    • H04M2203/10—Aspects of automatic or semi-automatic exchanges related to the purpose or context of the telephonic communication
    • H04M2203/1091—Fixed mobile conversion

Definitions

  • the present invention relates to a system for call forwarding between a wired communication network and a wireless communication network, and more particularly to a system and method for wired/wireless call forwarding which can forward call attempts on a wirele ' ss communication network to a wired communication network by using lines of payphones, and a dual-channel wireless terminal therefor.
  • wireless terminals have been popularized without distinction of age or sex. Accordingly, users can easily make phone calls anytime, anywhere and get necessary information by using their wireless terminals. However, communication service charges of the wireless terminals are too high in spite of the popularization, which makes the users unsatisfied.
  • payphones are much less used due to the popularization of the wireless terminals.
  • the payphones provide lower call charges and higher call quality than the wireless terminals, but do not have mobility, which is the most remarkable advantage of the wireless terminals.
  • resources such as lines of the payphones are used wastefully, and proceeds and maintenance/repair expenses are not balanced.
  • a mobile communication system has been developed from the first generation using analog frequency division multiple access and the second generation using digital time division multiple access and code division multiple access to the third generation, a mobile broadband system which guarantees mobility of terminals, passes the limit of regional voice dependent services of the general mobile communication services, and provides perfect multimedia services.
  • the IMT-2000 uses 2GHz for universal roaming, which is a worldwide shared frequency band appointed by the ITU.
  • 2GHz In a frequency bandwidth per channel which decides a data rate, digital cellular phones and PCS using the same technology in Korea attain 1.23MHz, but the LMT-2000 attains a maximum of 2Mbps. Accordingly, the LMT-2000 can transmit motion pictures as well as voice and data.
  • the second generation mobile communication services will be gradually absorbed by the third generation, but the wired communication services and the LMT-2000 will mutually develop each other.
  • a primary object of the present invention is to provide a system and method for wired/wireless call forwarding which can considerably cut down call charges by forwarding call attempts of wireless terminals to a wired network by using payphones adjacent to the wireless terminals.
  • Another object of the present invention is to provide a dual-channel wireless terminal fabricated by mounting a 900MHz band wireless transmission/reception module of excellent electric wave quality and characteristics on a wireless terminal, for attempting calls in a frequency band having a center frequency of 900MHz upon the user's request, and forwarding the call attempts to a wired network using lines of adjacent payphones.
  • a system for wired/wireless call forwarding including: a dual-channel wireless terminal switched into a first mode and a second mode, for performing wireless communication in different frequency bands in each mode; a call forwarding gateway connected to a plurality of lines of payphones by wire for communicating with a PSTN, when the dual-channel wireless terminal is switched into the second mode, the call forwarding gateway performing wireless communication with the dual-channel wireless terminal within a designated radius, when the dual-channel wireless terminal is switched into the second mode to attempt a call within the designated radius, the call forwarding gateway attempting the call through the PSTN by selecting one of the lines of the payphones; the PSTN receiving status information of the dual-channel wireless terminal from the call forwarding gateway, and transmitting call termination attempt to the call forwarding gateway including the dual-channel wireless terminal, when a wired telephone attempts the call termination to the dual-channel wireless terminal existing within the radius for communicating with the call forwarding gateway and switched into the second mode.
  • FIG. 1 is an exemplary diagram illustrating a communication network in which a system for wired/wireless call forwarding is used in accordance with the present invention
  • Fig. 2 is a detailed structure diagram illustrating a wired/wireless call forwarding gateway of Fig. 1;
  • Fig. 3 is a detailed structure diagram illustrating a dual-channel wireless terminal in accordance with the present invention
  • Fig. 4 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with one embodiment of the present invention
  • Fig. 5 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with another embodiment of the present invention.
  • Fig. 6 is an exemplary diagram illustrating another example of the communication network in which the system for wired/wireless call forwarding is used in accordance with the present invention
  • Fig. 7 is a detailed structure diagram illustrating a gateway exchange of Fig. 6;
  • Fig. 8 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with yet another embodiment of the present invention.
  • a dual-channel wireless terminal is fabricated by mounting a 900MHz band communication module on a wireless terminal for transmitting/receiving voice and data through a wireless communication network, such as a cellular phone, PCS and PDA. If necessary, the wireless terminal has a channel switching function. As compared with the PCS using a band of 1.8GHz, the 900MHz data communication shows a long electric wave reaching distance and excellent transmission and diffraction. Accordingly, it is less sensitive to environmental factors, such as climate, buildings and mountains, to reduce shadow areas. In this embodiment, the 900MHz band communication module is mounted on the wireless terminal, but different frequency bands can be selected in different communication environments.
  • Fig. 1 is an exemplary diagram illustrating a communication network in which a wired/wireless call forwarding gateway is used in accordance with the present invention.
  • the call forwarding gateway 20 is connected to a dual-channel wireless terminal 10 by wireless in a frequency band of 900MHz, and also connected to a payphone group 30 including a plurality of payphones 30-l ⁇ 30-n by wire, h addition, the dual-channel wireless terminal 10 is generally connected to communicate with a wireless communication system 50 through a base station 60 in a frequency band of 800MHz or 1.8GHz, and the payphone group 30 is connected to a PSTN 40.
  • the wireless communication system 50 represents a network provider who provides voice and data services by wireless.
  • Reference numeral 70 denotes a single channel wireless terminal 10 such as a cellular phone, PCS and PDA, and 80 denotes a wired telephone 80 which can attempt wired communication through the PSTN 40.
  • a communication module using a frequency band (for example, 800MHz or 1.8GHz band) for performing wireless communication through the wireless communication system 50 and a communication module using a frequency band (for example, 900MHz) for performing wired communication through the call forwarding gateway 20 are mounted on the dual-channel wireless terminal 10.
  • the communication modules can be incorporated or separately formed.
  • the user When the user does not stay in the area for communicating with the call forwarding gateway 20, the user switches the dual- channel wireless terminal 10 into a mode for communicating with the wireless communication system 50 (referred to as 'wireless communication mode'), and performs communication.
  • the electric wave reaching radius of the call forwarding gateway 20 can be expanded by controlling the discharge power of the call forwarding gateway 20.
  • the dual-channel wireless terminal 10 previously registers whether or not to use the call forwarding service in a wired exchange (not shown) of the PSTN 40, and periodically communicates with the call forwarding gateway 20, to periodically store the call forwarding gateway area in which the terminal 10 is currently located in the call forwarding gateway 20 and the wired exchange of the PSTN 40.
  • Modes of the dual- channel wireless terminal 10 are switched by function keys. For example, when the user intends to switch the wireless communication mode of the dual-channel wireless terminal 10 into the payphone mode, he/she presses a function key preset in the dual-channel wireless terminal 10 (for example, 900*).
  • a plurality of call forwarding gateways 20 can be installed to manage the payphone group 30 at intervals of a predetermined distance.
  • a communication line of the idle state payphone 30-l ⁇ 30-n is selected from the payphone group 30, to compose a communication network of the dual-channel wireless terminal 10 - call forwarding gateway 20 - payphone 30-l ⁇ 30-n - PSTN 40.
  • the wired exchange of the PSTN 40 confirms the call forwarding gateway 20 in which the dual-channel wireless terminal 10 is located, transmits the call attempt request signal to the call forwarding gateway 20, and sets the call among the caller wired telephone 80 - payphone 30 - call forwarding gateway 20 - recipient dual-channel wireless terminal 10, to reduce call charges of the caller.
  • the recipient dual-channel wireless terminal 10 must be switched into the payphone mode before the termination, and continuously exchange signals with the call forwarding gateway 20 for location registration.
  • Fig. 2 is a detailed structure diagram illustrating the wired/wireless call forwarding gateway 20 of Fig. 1.
  • the call forwarding gateway 20 includes a payphone managing means 200, a location information transmitting means 202, a payphone selecting means 204, a wireless-wired call exchanging means 206, a wired-wireless call exchanging means 208, a power sensing means 210, a warning tone sending means 212, a charging means 214, a communication network interface 216, a control unit 220 and a database 230.
  • the database 230 is comprised of a payphone DB 232 and a charging information DB 234. The databases can be incorporated or separately formed.
  • the payphone managing means 200 stores information of numbers and using states (call or idle state) of each of the payphones 30-l ⁇ 30-n of the payphone group 30 within the designated distance from the call forwarding gateway 20 in the payphone DB 232, and manages the information.
  • the location information transmitting means 202 continuously transmits and receives signals to/from the whole dual-channel wireless terminals 10 within the communication radius of the call forwarding gateway 20, and transmits the number of the dual-channel wireless terminal 10 and the ID number of the call forwarding gateway 20 to the wired exchange of the PSTN 40, so that the wired exchange can recognize the call forwarding gateway area in which the dual-channel wireless terminal 10 is located.
  • the payphone selecting means 204 selects one idle state payphone 30-l ⁇ 30-n from the payphone group 30 connected to the call forwarding gateway 20.
  • the call forwarding gateway 20 stores line numbers of the whole payphones 30-l ⁇ 30-n of the connected payphone group 30 in the payphone DB 232 in the numerical order.
  • the call forwarding gateway 20 selects the idle line upon the call attempt of the dual-channel wireless terminal 10, it sequentially searches the line number table and selects the first idle line.
  • the wireless-wired call exchanging means 206 connects the call attempt of the dual-channel wireless terminal 10 to the PSTN 40 through the call forwarding gateway 20 and the line of the payphone 30-l ⁇ 30-n, so that the wired exchange may request call setup to the caller terminal.
  • the wired-wireless call exchanging means 208 receives the call attempt request from the PSTN 40 and transmits a ring signal to the dual-channel wireless terminal 10.
  • the power sensing means 210 senses the intensity of signals transmitted or received to/from the whole dual-channel wireless terminals 10 within the communication radius of the call forwarding gateway 20, and thus confirms whether the dual-channel wireless terminals 10 can perform communication through the call forwarding gateway 20. In the case of the idle state dual-channel wireless terminal 10 existing within the communication radius of the call forwarding gateway 20, if the transmission/reception power of the terminal 10 sensed by the power sensing means 210 is smaller than a designated value, the terminal 10 cannot attempt a call through the call forwarding gateway 20 even in the payphone mode.
  • the warning tone sending means 212 notifies it to the dual- channel wireless terminal 10 so that the user can recognize it.
  • the warning tone sending means 212 sends a warning tone for notifying call switching to the terminal 10, so that the user can prepare for sudden call switching without unpleasantness.
  • the power sensing means 210 senses the intensity of the signal from the dual-channel wireless terminal 10. If the intensity of the signal is larger than a designated value, the power sensing means 210 transmits a response signal to switch the dual-channel wireless terminal 10 into the payphone mode. If the intensity of the signal is smaller than the designated value, the power sensing means 210 notifies that the payphone mode is not available by the warning tone sending means 212 to the dual-channel wireless terminal 10. Here, a message, such as 'No service area' or 'Wait for a second' can be sent with the warning tone.
  • the warning tone sending means 212 sends a corresponding warning tone to the dual-channel wireless terminal 10.
  • the warning tone sending means 212 generates a warning tone or sends a guide message such as 'Line is busy'.
  • the charging means 214 generates charging information based on call duration of the user of the dual-channel wireless terminal 10 and line information of the payphone, stores the charging information in the charging information DB 234, and periodically transmits it to the PSTN 40. Accordingly, the communication charges of the dual-channel wireless terminal 10 are not added to the service charges of the wireless communication system 50, but added to the service charges of the wired telephone 80.
  • the communication network interface 216 performs wired/wireless communication between the dual-channel wireless terminal 10 switched into the payphone mode and the payphone group 30, and the control unit 220 controls the whole operations of the constitutional elements.
  • Fig. 3 is a detailed structure diagram illustrating the dual-channel wireless terminal 10 in accordance with the present invention.
  • the dual-channel wireless terminal 10 includes a control unit
  • a memory means 102 a channel changing means 104, a key input means 106, a first communication network interface 108, 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 changing means 104 switches the communication mode of the dual-channel wireless terminal 10 into the wireless communication mode or payphone mode.
  • the current mode and transmission/reception state of the dual-channel wireless terminal 10 are displayed on the display unit 118.
  • a message such as 'Switched into payphone mode', 'Wait for a second' or 'No service area' is displayed so that the user can be informed of the current state of the terminal 10.
  • the messages relating to service changes are stored in the memory means 102 of the dual-channel wireless terminal 10, and selected and displayed according to the current state, or the corresponding message is downloaded from the call forwarding gateway 20 and displayed.
  • the first communication network interface 108 enables the first communication module 112 to communicate with the wireless communication system 50 through the base station 60, and when the dual-channel wireless terminal 10 is switched into the payphone mode, the second communication network interface 110 enables the second communication module 114 to communicate with the PSTN 40 through the payphones 30-l ⁇ 30-n.
  • Reference numeral 100 denotes the control unit.
  • the commercialized wireless terminal can be easily converted into the dual-channel wireless terminal.
  • Fig. 4 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with one embodiment of the present invention.
  • the dual- channel wireless terminal 10 is switched into the payphone mode for call attempts.
  • the channel changing means 104 switches the communication mode into the payphone mode to change channels (S101). Preferably, channel changes are displayed on the display unit 118.
  • the communication mode of the dual-channel wireless terminal 10 is switched into the payphone mode, if the user attempts a call by inputting a number of a wired or wireless termmal of a wanted recipient (SI 02), the dual-channel wireless terminal 10 can communicate with the call forwarding gateway 20, but cannot communicate with the wireless communication system 50. Accordingly, the call attempt of the dual-channel wireless terminal 10 is not transmitted to the wireless communication system 50 but to the call forwarding gateway 20.
  • the call forwarding gateway 20 preferably confirms call charges payment particulars of the user of the dual-channel wireless terminal 10 fixed by the charging means 210 by referring to the charging information DB 234, to authenticate the user (SI 03).
  • the payphone selecting means 204 selects the idle state payphone by referring to the payphone DB 232 (SI 04).
  • the wireless- wired call exchanging means 206 of the call forwarding gateway 20 transmits the call attempt request of the dual-channel wireless terminal 10 to the PSTN 40 through the selected payphone (SI 05 and SI 06), and thus a speech path is formed between the dual-channel wireless terminal 10 and the PSTN 40 (SI 07).
  • the PSTN 40 confirms recipient information and transmits a ring signal to the wired or wireless terminal of the recipient.
  • the charging means 210 stores call duration between the user of the dual-channel wireless terminal 10 and the recipient in the charging information DB 236, and transmits it to the
  • the warning tone sending means 212 notifies it to the terminal 10.
  • the user switches the dual-channel wireless terminal 10 into the payphone mode and attempts a call, the call does not pass through the wireless commumcation system 50, which cuts down call charges.
  • Fig. 5 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with another embodiment of the present invention.
  • the user of the wired terminal attempts a call to the dual-channel wireless terminal 10.
  • the user of the dual-channel wireless terminal 10 must register whether or not to use services in the wired exchange of the PSTN 40, switch the dual-channel wireless te ⁇ ninal 10 into the payphone mode, and continuously transmit and receive signals to/from the call forwarding gateway 20 for location registration.
  • the call forwarding gateway 20 must periodically notify states of the whole dual-channel wireless terminals 10 within its communication radius to the wired exchange (S200).
  • the wired exchange of the PSTN 40 extracts recipient information, confirms whether the recipient is a registered user of the call forwarding service (S202), and extracts the ID number of the call forwarding gateway 20 in which the dual-channel wireless terminal 10 is located by referring to location information of the dual-channel wireless terminal 10 from the location information transmitting means 202 (S203).
  • the idle state payphone 30-l ⁇ 30-n is selected from the payphone group 30 of the call forwarding gateway 20 (S204), and the call attempt request of the caller and the number of the requested dual-channel wireless terminal 10 are transmitted to the call forwarding gateway 20 through the selected payphone (S205). Therefore, the wired- wireless call exchanging means 208 of the call forwarding gateway 20 generates a ring signal to the dual-channel wireless terminal 10 (S206). When the dual-channel wireless terminal 10 responds to the ring signal, a speech path is formed between the caller terminal and the dual-channel wireless terminal 10 (S207).
  • the warning tone sending means 212 notifies it to the terminal 10.
  • the call attempted to the dual-channel wireless terminal 10 by the caller is directly transmitted to the wired network without passing through the wireless network, which reduces call charges of the caller.
  • Fig. 6 is an exemplary diagram illustrating another example of the communication network in which the wired/wireless call forwarding gateway is used in accordance with the present invention.
  • a plurality of call forwarding gateways 20-l ⁇ 20-n are connected to the dual-channel wireless terminals 10 existing in each communication radius of 900MHz frequency band by wireless, connected to adjacent payphone groups 300- l ⁇ 300-n by wire, and connected to a gateway exchange 400.
  • the gateway exchange 400 manages information of each of the call forwarding gateways 20-l ⁇ 20-n, and routes a speech path set for the current dual-channel wireless terminal 10 to a line of another payphone upon the request of the call forwarding gateway.
  • the call forwarding gateway requests the gateway exchange 400 to select another call forwarding gateway for call routing. Accordingly, the gateway exchange 400 transmits information of the corresponding dual-channel wireless terminal 10 to the plurality of call forwarding gateways adjacent to the current call forwarding gateway to check the transmission/reception power, selects the call forwarding gateway having the highest transmission/reception power, and requests the call forwarding gateway to select the line of the idle state payphone.
  • the gateway exchange 400 routes the speech path of the dual-channel wireless terminal 10 to the call forwarding gateway, to prevent interruption of the call.
  • the functions of the dual-channel wireless terminal 10 and the call forwarding gateways 20-l ⁇ 20-n are similar or identical to the structures of Figs. 1 to 3, and thus detailed explanations thereof are omitted.
  • Fig. 7 is a detailed structure diagram illustrating the gateway exchange 400 of Fig. 6.
  • the gateway exchange 400 includes a control unit 402, a call forwarding gateway managing means 404, a call forwarding gateway selecting means 406, a line selection requesting means 408, a call routing means 410, a communication network interface 412 and a database 414.
  • the call forwarding gateway managing means 404 stores ID numbers and location information of each of the call forwarding gateways 20-l ⁇ 20-n in the database 414, and manages them.
  • the call forwarding gateway selecting means 406 transmits information of the corresponding dual-channel wireless terminal 10 to a plurality of call forwarding gateways adjacent to the call forwarding gateway • 20-l ⁇ 20-n in order to check the transmission/reception power between the call forwarding gateways and the dual-channel wireless terminal 10, and selects the call forwarding gateway having the highest transmission/reception power.
  • the line selection requesting means 408 requests the call forwarding gateway selected by the call forwarding gateway selecting means 406 to select the idle line from the lines of the payphones of the connected payphone group.
  • the call routing means 410 When the call routing means 410 is notified that the call forwarding gateway selected by the call forwarding gateway selecting means 406 has selected the line of the idle state payphone, the call routing means 410 routes the speech path of the existing call forwarding gateway to the re-selected call forwarding gateway and the line of the payphone.
  • Fig. 8 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with yet another embodiment of the present invention.
  • the call forwarding gateway and the line of the payphone which the dual-channel wireless terminal 10 is firstly connected to are referred to as a first call forwarding gateway and a first payphone line
  • the call forwarding gateway and the line of the payphone re-selected due to reduction of the transmission/reception power are referred to as a second call forwarding gateway and a second payphone line.
  • the power sensing means of the first call forwarding gateway continuously senses the transmission/reception power between the dual-channel wireless terminal 10 and the first call forwarding gateway (S302). h the case that the transmission/reception power between the dual-channel wireless terminal 10 and the first call forwarding gateway is smaller than the designated value because of the movement of the dual-channel wireless terminal 10 or peripheral interference signals, the first- call forwarding gateway requests routing to the gateway exchange 400 (S303). That is, when the transmission/reception power between the dual- channel wireless terminal 10 and the first call forwarding gateway is reduced, the first call forwarding gateway decides that the dual-channel wireless terminal 10 exists on its communication radius boundary, and requests the gateway exchange 400 to route the call to the adjacent call forwarding gateway.
  • the first call forwarding gateway preferably transmits its ID number and the ID number of the dual-channel wireless terminal 10 to the gateway exchange 400.
  • the call forwardmg gateway selecting means 406 of the gateway exchange 400 receiving the routing request from the first call forwarding gateway confirms location information of the first call forwarding gateway by referring to the database 414 by the ID number of the first call forwarding gateway, and transmits information (ID number, etc.) of the dual-channel wireless terminal 10 to the plurality of adjacent call forwarding gateways, to check the transmission/reception power.
  • the call forwarding gateway selecting means 406 selects the call forwarding gateway having the highest transmission/reception power
  • the line selection requesting means 408 requests the second call forwarding gateway to select the line of the idle state payphone (S305).
  • the payphone selecting means of the second call forwarding gateway selects the line of the idle state payphone from the connected payphone group (S306), and notifies the result to the gateway exchange 400 (S307). Therefore, the call routing means 410 of the gateway exchange 400 accesses the second payphone line through the second call forwarding gateway (S308), and transmits routing information to the dual-channel wireless terminal 10 (S309). That is, the call routing means 410 transmits access information of the second call forwarding system to set the speech path. As a result, the speech path of the dual-channel wireless terminal 10 - second call forwarding gateway - second payphone line - recipient terminal is reset (S310), so that the user can continuously talk over the phone without experiencing call switching or feeling reset of the speech path (S311).
  • the communication module for performing wireless communication in a frequency band of 900MHz is mounted on the wireless terminal such as a cellular phone, PCS and PDA, and the call forwarding gateway is connected to the plurality of payphones for performing wireless communication in a frequency band of 900MHz.
  • the wireless terminal such as a cellular phone, PCS and PDA
  • the call forwarding gateway is connected to the plurality of payphones for performing wireless communication in a frequency band of 900MHz.
  • the call attempt is transmitted to the
  • the call attempts on the wireless network are forwarded into the wired network, to cut down call charges.
  • the wired terminal attempts a call to the dual-channel wireless terminal within the communication radius of the call forwarding gateway the call attempt request of the caller is directly transmitted through the wired network, without passing through the wireless communication system, which reduces call charges of the caller.
  • the gateway exchange for managing states of the plurality of call forwarding gateways is installed. As a result, even if the user moves to another call forwarding gateway area during the call, he/she can continuously use the service without call switching.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The present invention discloses a system and method for wired/wireless call forwarding which can forward call attempts on a wireless communication network to a wired communication network by using lines of payphones, and a dual-channel wireless terminal therefor. The system for wired/wireless call forwarding includes a dual-channel wireless terminal for performing wireless communication in different frequency bands in a first mode and a second mode, a call forwarding gateway connected to a plurality of lines of payphones by wire for performing wireless communication with the dual-channel wireless terminal in a designated frequency band, when the dual-channel wireless terminal attempts a call, the call forwarding gateway selecting one of the lines of the payphones to attempt the call through a PSTN, and the PSTN receiving status information of the dual-channel wireless terminal from the call forwarding gateway, when a wired telephone attempts call termination to the dual-channel wireless terminal switched into the second mode, the PSTN transmitting the termination attempt to the call forwarding gateway including the dual-channel wireless terminal. As a result, the call attempts on the wireless network are forwarded into the wired network, to cut down call charges.

Description

SYSTEM AND METHOD FOR WIRED/WIRELESS CALL EXCHANGING AND DUAL-CHANNEL WIRELESS TERMINAL THEREFOR
TECHNICAL FIELD
The present invention relates to a system for call forwarding between a wired communication network and a wireless communication network, and more particularly to a system and method for wired/wireless call forwarding which can forward call attempts on a wirele'ss communication network to a wired communication network by using lines of payphones, and a dual-channel wireless terminal therefor.
BACKGROUND ART
Recently, wireless terminals have been popularized without distinction of age or sex. Accordingly, users can easily make phone calls anytime, anywhere and get necessary information by using their wireless terminals. However, communication service charges of the wireless terminals are too high in spite of the popularization, which makes the users unsatisfied.
In addition, payphones are much less used due to the popularization of the wireless terminals. The payphones provide lower call charges and higher call quality than the wireless terminals, but do not have mobility, which is the most remarkable advantage of the wireless terminals. As a result, resources such as lines of the payphones are used wastefully, and proceeds and maintenance/repair expenses are not balanced.
On the other hand, a mobile communication system has been developed from the first generation using analog frequency division multiple access and the second generation using digital time division multiple access and code division multiple access to the third generation, a mobile broadband system which guarantees mobility of terminals, passes the limit of regional voice dependent services of the general mobile communication services, and provides perfect multimedia services. As compared with the general mobile communication system, the IMT-2000 uses 2GHz for universal roaming, which is a worldwide shared frequency band appointed by the ITU. In a frequency bandwidth per channel which decides a data rate, digital cellular phones and PCS using the same technology in Korea attain 1.23MHz, but the LMT-2000 attains a maximum of 2Mbps. Accordingly, the LMT-2000 can transmit motion pictures as well as voice and data. The second generation mobile communication services will be gradually absorbed by the third generation, but the wired communication services and the LMT-2000 will mutually develop each other.
DISCLOSURE OF THE INVENTION
The present invention is achieved to solve the above problems. A primary object of the present invention is to provide a system and method for wired/wireless call forwarding which can considerably cut down call charges by forwarding call attempts of wireless terminals to a wired network by using payphones adjacent to the wireless terminals.
Another object of the present invention is to provide a dual-channel wireless terminal fabricated by mounting a 900MHz band wireless transmission/reception module of excellent electric wave quality and characteristics on a wireless terminal, for attempting calls in a frequency band having a center frequency of 900MHz upon the user's request, and forwarding the call attempts to a wired network using lines of adjacent payphones. hi the case that the user makes a call by switching the communication module of the wireless terminal into 900MHz, if he/she leaves the 900MHz communication area, a speech path is routed to an adjacent communication area, so that the user can continuously use the service without call drop. In order to achieve the above-described objects of the invention, there is provided a system for wired/wireless call forwarding including: a dual-channel wireless terminal switched into a first mode and a second mode, for performing wireless communication in different frequency bands in each mode; a call forwarding gateway connected to a plurality of lines of payphones by wire for communicating with a PSTN, when the dual-channel wireless terminal is switched into the second mode, the call forwarding gateway performing wireless communication with the dual-channel wireless terminal within a designated radius, when the dual-channel wireless terminal is switched into the second mode to attempt a call within the designated radius, the call forwarding gateway attempting the call through the PSTN by selecting one of the lines of the payphones; the PSTN receiving status information of the dual-channel wireless terminal from the call forwarding gateway, and transmitting call termination attempt to the call forwarding gateway including the dual-channel wireless terminal, when a wired telephone attempts the call termination to the dual-channel wireless terminal existing within the radius for communicating with the call forwarding gateway and switched into the second mode.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein: Fig. 1 is an exemplary diagram illustrating a communication network in which a system for wired/wireless call forwarding is used in accordance with the present invention;
Fig. 2 is a detailed structure diagram illustrating a wired/wireless call forwarding gateway of Fig. 1; Fig. 3 is a detailed structure diagram illustrating a dual-channel wireless terminal in accordance with the present invention;
Fig. 4 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with one embodiment of the present invention;
Fig. 5 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with another embodiment of the present invention;
Fig. 6 is an exemplary diagram illustrating another example of the communication network in which the system for wired/wireless call forwarding is used in accordance with the present invention;
Fig. 7 is a detailed structure diagram illustrating a gateway exchange of Fig. 6; and
Fig. 8 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with yet another embodiment of the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
A system and method for wired/wireless call forwarding, and a dual-channel wireless terminal therefor in accordance with preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
A dual-channel wireless terminal is fabricated by mounting a 900MHz band communication module on a wireless terminal for transmitting/receiving voice and data through a wireless communication network, such as a cellular phone, PCS and PDA. If necessary, the wireless terminal has a channel switching function. As compared with the PCS using a band of 1.8GHz, the 900MHz data communication shows a long electric wave reaching distance and excellent transmission and diffraction. Accordingly, it is less sensitive to environmental factors, such as climate, buildings and mountains, to reduce shadow areas. In this embodiment, the 900MHz band communication module is mounted on the wireless terminal, but different frequency bands can be selected in different communication environments.
Fig. 1 is an exemplary diagram illustrating a communication network in which a wired/wireless call forwarding gateway is used in accordance with the present invention.
Referring to Fig. 1, the call forwarding gateway 20 is connected to a dual-channel wireless terminal 10 by wireless in a frequency band of 900MHz, and also connected to a payphone group 30 including a plurality of payphones 30-l~30-n by wire, h addition, the dual-channel wireless terminal 10 is generally connected to communicate with a wireless communication system 50 through a base station 60 in a frequency band of 800MHz or 1.8GHz, and the payphone group 30 is connected to a PSTN 40. Here, the wireless communication system 50 represents a network provider who provides voice and data services by wireless. Reference numeral 70 denotes a single channel wireless terminal 10 such as a cellular phone, PCS and PDA, and 80 denotes a wired telephone 80 which can attempt wired communication through the PSTN 40.
A communication module using a frequency band (for example, 800MHz or 1.8GHz band) for performing wireless communication through the wireless communication system 50 and a communication module using a frequency band (for example, 900MHz) for performing wired communication through the call forwarding gateway 20 are mounted on the dual-channel wireless terminal 10. The communication modules can be incorporated or separately formed. When the user of the dual-channel wireless terminal 10 stays in an area for communicating with the call forwarding gateway 20 (for example, within the 2Km radius), the user switches the dual-channel wireless terminal 10 into a mode for communicating with the PSTN 40 via the call forwardmg gateway 20 and the payphones 30-l~30-n (referred to as 'payphone mode'), and performs voice and data communication in the payphone mode. When the user does not stay in the area for communicating with the call forwarding gateway 20, the user switches the dual- channel wireless terminal 10 into a mode for communicating with the wireless communication system 50 (referred to as 'wireless communication mode'), and performs communication. Here, the electric wave reaching radius of the call forwarding gateway 20 can be expanded by controlling the discharge power of the call forwarding gateway 20.
Preferably, the dual-channel wireless terminal 10 previously registers whether or not to use the call forwarding service in a wired exchange (not shown) of the PSTN 40, and periodically communicates with the call forwarding gateway 20, to periodically store the call forwarding gateway area in which the terminal 10 is currently located in the call forwarding gateway 20 and the wired exchange of the PSTN 40. Modes of the dual- channel wireless terminal 10 are switched by function keys. For example, when the user intends to switch the wireless communication mode of the dual-channel wireless terminal 10 into the payphone mode, he/she presses a function key preset in the dual-channel wireless terminal 10 (for example, 900*).
A plurality of call forwarding gateways 20 can be installed to manage the payphone group 30 at intervals of a predetermined distance. When the user switches the dual-channel wireless terminal 10 into the payphone mode and attempts a call, a communication line of the idle state payphone 30-l~30-n is selected from the payphone group 30, to compose a communication network of the dual-channel wireless terminal 10 - call forwarding gateway 20 - payphone 30-l~30-n - PSTN 40.
On the other hand, when the user of the wired telephone 80 attempts a call to the dual-channel wireless terminal 10 within the communication radius of the call forwarding gateway 20, the wired exchange of the PSTN 40 confirms the call forwarding gateway 20 in which the dual-channel wireless terminal 10 is located, transmits the call attempt request signal to the call forwarding gateway 20, and sets the call among the caller wired telephone 80 - payphone 30 - call forwarding gateway 20 - recipient dual-channel wireless terminal 10, to reduce call charges of the caller. In this case, the recipient dual-channel wireless terminal 10 must be switched into the payphone mode before the termination, and continuously exchange signals with the call forwarding gateway 20 for location registration.
Fig. 2 is a detailed structure diagram illustrating the wired/wireless call forwarding gateway 20 of Fig. 1.
As illustrated in Fig. 2, the call forwarding gateway 20 includes a payphone managing means 200, a location information transmitting means 202, a payphone selecting means 204, a wireless-wired call exchanging means 206, a wired-wireless call exchanging means 208, a power sensing means 210, a warning tone sending means 212, a charging means 214, a communication network interface 216, a control unit 220 and a database 230. Here, the database 230 is comprised of a payphone DB 232 and a charging information DB 234. The databases can be incorporated or separately formed.
The payphone managing means 200 stores information of numbers and using states (call or idle state) of each of the payphones 30-l~30-n of the payphone group 30 within the designated distance from the call forwarding gateway 20 in the payphone DB 232, and manages the information. The location information transmitting means 202 continuously transmits and receives signals to/from the whole dual-channel wireless terminals 10 within the communication radius of the call forwarding gateway 20, and transmits the number of the dual-channel wireless terminal 10 and the ID number of the call forwarding gateway 20 to the wired exchange of the PSTN 40, so that the wired exchange can recognize the call forwarding gateway area in which the dual-channel wireless terminal 10 is located.
When the user of the dual-channel wireless terminal 10 switches the call mode into the payphone mode and attempts a call, the payphone selecting means 204 selects one idle state payphone 30-l~30-n from the payphone group 30 connected to the call forwarding gateway 20. The call forwarding gateway 20 stores line numbers of the whole payphones 30-l~30-n of the connected payphone group 30 in the payphone DB 232 in the numerical order. When the call forwarding gateway 20 selects the idle line upon the call attempt of the dual-channel wireless terminal 10, it sequentially searches the line number table and selects the first idle line.
When the payphone selecting means 204 selects the line of the payphone 30- l~30-n, the wireless-wired call exchanging means 206 connects the call attempt of the dual-channel wireless terminal 10 to the PSTN 40 through the call forwarding gateway 20 and the line of the payphone 30-l~30-n, so that the wired exchange may request call setup to the caller terminal.
When the wired telephone 80 attempts a call to the dual-channel wireless terminal 10 existing within the communication radius of the call forwarding gateway 20 and switched into the payphone mode, the wired-wireless call exchanging means 208 receives the call attempt request from the PSTN 40 and transmits a ring signal to the dual-channel wireless terminal 10.
The power sensing means 210 senses the intensity of signals transmitted or received to/from the whole dual-channel wireless terminals 10 within the communication radius of the call forwarding gateway 20, and thus confirms whether the dual-channel wireless terminals 10 can perform communication through the call forwarding gateway 20. In the case of the idle state dual-channel wireless terminal 10 existing within the communication radius of the call forwarding gateway 20, if the transmission/reception power of the terminal 10 sensed by the power sensing means 210 is smaller than a designated value, the terminal 10 cannot attempt a call through the call forwarding gateway 20 even in the payphone mode. The warning tone sending means 212 notifies it to the dual- channel wireless terminal 10 so that the user can recognize it. In the case of the call state dual-channel wireless terminal 10 existing within the communication radius of the call forwarding gateway 20, if the transmission/reception power of the terminal 10 sensed by the power sensing means 210 is smaller than the designated value, the warning tone sending means 212 sends a warning tone for notifying call switching to the terminal 10, so that the user can prepare for sudden call switching without unpleasantness.
When the user switches the dual-channel wireless terminal 10 into the payphone mode by inputting a designated function key, the power sensing means 210 senses the intensity of the signal from the dual-channel wireless terminal 10. If the intensity of the signal is larger than a designated value, the power sensing means 210 transmits a response signal to switch the dual-channel wireless terminal 10 into the payphone mode. If the intensity of the signal is smaller than the designated value, the power sensing means 210 notifies that the payphone mode is not available by the warning tone sending means 212 to the dual-channel wireless terminal 10. Here, a message, such as 'No service area' or 'Wait for a second' can be sent with the warning tone.
That is, when the call cannot be attempted due to the low transmission/reception power and when the call may be switched in the call state due to reduction of the transmission/reception power, if the intensity of the signal of the dual-channel wireless terminal 10 intended to be switched into the payphone mode is smaller than the designated value, the warning tone sending means 212 sends a corresponding warning tone to the dual-channel wireless terminal 10. hi addition, when another user intends to use the payphone selected for the call attempt of the dual-channel wireless terminal 10, the warning tone sending means 212 generates a warning tone or sends a guide message such as 'Line is busy'.
The charging means 214 generates charging information based on call duration of the user of the dual-channel wireless terminal 10 and line information of the payphone, stores the charging information in the charging information DB 234, and periodically transmits it to the PSTN 40. Accordingly, the communication charges of the dual-channel wireless terminal 10 are not added to the service charges of the wireless communication system 50, but added to the service charges of the wired telephone 80. The communication network interface 216 performs wired/wireless communication between the dual-channel wireless terminal 10 switched into the payphone mode and the payphone group 30, and the control unit 220 controls the whole operations of the constitutional elements.
Fig. 3 is a detailed structure diagram illustrating the dual-channel wireless terminal 10 in accordance with the present invention.
As depicted in Fig. 3, the dual-channel wireless terminal 10 includes a control unit
100, a memory means 102, a channel changing means 104, a key input means 106, a first communication network interface 108, 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.
When the user of the dual-channel wireless terminal 10 inputs a switching command for selecting one of the wireless communication mode or payphone mode to the input means 106 by operating the keypad unit 116, the channel changing means 104 switches the communication mode of the dual-channel wireless terminal 10 into the wireless communication mode or payphone mode. Preferably, the current mode and transmission/reception state of the dual-channel wireless terminal 10 are displayed on the display unit 118. For example, when the user inputs a function key for switching the communication mode into the payphone mode, a message, such as 'Switched into payphone mode', 'Wait for a second' or 'No service area' is displayed so that the user can be informed of the current state of the terminal 10. The messages relating to service changes are stored in the memory means 102 of the dual-channel wireless terminal 10, and selected and displayed according to the current state, or the corresponding message is downloaded from the call forwarding gateway 20 and displayed.
When the dual-channel wireless terminal 10 is switched into the wireless communication mode, the first communication network interface 108 enables the first communication module 112 to communicate with the wireless communication system 50 through the base station 60, and when the dual-channel wireless terminal 10 is switched into the payphone mode, the second communication network interface 110 enables the second communication module 114 to communicate with the PSTN 40 through the payphones 30-l~30-n. Reference numeral 100 denotes the control unit. When the two communication modules are used, the commercialized wireless terminal can be easily converted into the dual-channel wireless terminal. Fig. 4 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with one embodiment of the present invention. Here, the dual- channel wireless terminal 10 is switched into the payphone mode for call attempts.
When the user of the dual-channel wireless terminal 10 staying within the communication radius of the call forwarding gateway 20 operates the keypad unit 116 to switch the communication mode, the channel changing means 104 switches the communication mode into the payphone mode to change channels (S101). Preferably, channel changes are displayed on the display unit 118. When the communication mode of the dual-channel wireless terminal 10 is switched into the payphone mode, if the user attempts a call by inputting a number of a wired or wireless termmal of a wanted recipient (SI 02), the dual-channel wireless terminal 10 can communicate with the call forwarding gateway 20, but cannot communicate with the wireless communication system 50. Accordingly, the call attempt of the dual-channel wireless terminal 10 is not transmitted to the wireless communication system 50 but to the call forwarding gateway 20.
Here, the call forwarding gateway 20 preferably confirms call charges payment particulars of the user of the dual-channel wireless terminal 10 fixed by the charging means 210 by referring to the charging information DB 234, to authenticate the user (SI 03). When the user of the dual-channel wireless terminal 10 proves to be a legal user, the payphone selecting means 204 selects the idle state payphone by referring to the payphone DB 232 (SI 04). Thereafter, the wireless- wired call exchanging means 206 of the call forwarding gateway 20 transmits the call attempt request of the dual-channel wireless terminal 10 to the PSTN 40 through the selected payphone (SI 05 and SI 06), and thus a speech path is formed between the dual-channel wireless terminal 10 and the PSTN 40 (SI 07).
Although not illustrated, after the speech path is formed between the dual-channel wireless terminal 10 and the PSTN 40, the PSTN 40 confirms recipient information and transmits a ring signal to the wired or wireless terminal of the recipient. In addition, the charging means 210 stores call duration between the user of the dual-channel wireless terminal 10 and the recipient in the charging information DB 236, and transmits it to the
PSTN 40 and the wireless communication system 50, if necessary. After the step (SI 07) for forming the speech path, when the user of the dual- channel wireless terminal 10 moves, if the power sensing means 210 senses that the transmission/reception power between the terminal 10 and the call forwarding gateway 20 is smaller than the designated value, the warning tone sending means 212 notifies it to the terminal 10. As described above, when the user switches the dual-channel wireless terminal 10 into the payphone mode and attempts a call, the call does not pass through the wireless commumcation system 50, which cuts down call charges.
Fig. 5 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with another embodiment of the present invention. Here, the user of the wired terminal attempts a call to the dual-channel wireless terminal 10.
For this, the user of the dual-channel wireless terminal 10 must register whether or not to use services in the wired exchange of the PSTN 40, switch the dual-channel wireless teπninal 10 into the payphone mode, and continuously transmit and receive signals to/from the call forwarding gateway 20 for location registration. In addition, the call forwarding gateway 20 must periodically notify states of the whole dual-channel wireless terminals 10 within its communication radius to the wired exchange (S200).
When the caller using the wired terminal 80 attempts a call to the dual-channel wireless terminal 10 (S201), the wired exchange of the PSTN 40 extracts recipient information, confirms whether the recipient is a registered user of the call forwarding service (S202), and extracts the ID number of the call forwarding gateway 20 in which the dual-channel wireless terminal 10 is located by referring to location information of the dual-channel wireless terminal 10 from the location information transmitting means 202 (S203).
The idle state payphone 30-l~30-n is selected from the payphone group 30 of the call forwarding gateway 20 (S204), and the call attempt request of the caller and the number of the requested dual-channel wireless terminal 10 are transmitted to the call forwarding gateway 20 through the selected payphone (S205). Therefore, the wired- wireless call exchanging means 208 of the call forwarding gateway 20 generates a ring signal to the dual-channel wireless terminal 10 (S206). When the dual-channel wireless terminal 10 responds to the ring signal, a speech path is formed between the caller terminal and the dual-channel wireless terminal 10 (S207).
In this case, when the user of the dual-channel wireless terminal 10 moves, if the power sensing means 210 senses that the transmission/reception power between the terminal 10 and the call forwarding gateway 20 is smaller than the designated value, the warning tone sending means 212 notifies it to the terminal 10.
In this embodiment, the call attempted to the dual-channel wireless terminal 10 by the caller is directly transmitted to the wired network without passing through the wireless network, which reduces call charges of the caller.
Fig. 6 is an exemplary diagram illustrating another example of the communication network in which the wired/wireless call forwarding gateway is used in accordance with the present invention. When the dual-channel wireless terminal whose speech path has been set through the call forwarding gateway leaves the communication radius of the call forwarding gateway, namely when the transmission/reception power becomes smaller than the designated value, the call is routed to a line of a payphone of an adjacent call forwarding gateway.
As illustrated in Fig. 6, a plurality of call forwarding gateways 20-l~20-n are connected to the dual-channel wireless terminals 10 existing in each communication radius of 900MHz frequency band by wireless, connected to adjacent payphone groups 300- l~300-n by wire, and connected to a gateway exchange 400. The gateway exchange 400 manages information of each of the call forwarding gateways 20-l~20-n, and routes a speech path set for the current dual-channel wireless terminal 10 to a line of another payphone upon the request of the call forwarding gateway. For example, when the dual-channel wireless terminal 10 making a call via the call forwarding gateway is about to leave the communication radius of the call forwarding gateway, namely when the transmission/reception power is sensed smaller than the designated value, the call forwarding gateway requests the gateway exchange 400 to select another call forwarding gateway for call routing. Accordingly, the gateway exchange 400 transmits information of the corresponding dual-channel wireless terminal 10 to the plurality of call forwarding gateways adjacent to the current call forwarding gateway to check the transmission/reception power, selects the call forwarding gateway having the highest transmission/reception power, and requests the call forwarding gateway to select the line of the idle state payphone. When the call forwarding gateway selects the line of the payphone, the gateway exchange 400 routes the speech path of the dual-channel wireless terminal 10 to the call forwarding gateway, to prevent interruption of the call. In this embodiment, the functions of the dual-channel wireless terminal 10 and the call forwarding gateways 20-l~20-n are similar or identical to the structures of Figs. 1 to 3, and thus detailed explanations thereof are omitted.
Fig. 7 is a detailed structure diagram illustrating the gateway exchange 400 of Fig. 6. The gateway exchange 400 includes a control unit 402, a call forwarding gateway managing means 404, a call forwarding gateway selecting means 406, a line selection requesting means 408, a call routing means 410, a communication network interface 412 and a database 414.
The call forwarding gateway managing means 404 stores ID numbers and location information of each of the call forwarding gateways 20-l~20-n in the database 414, and manages them. When receiving a routing request from the call forwarding gateway 20- l~20-n, the call forwarding gateway selecting means 406 transmits information of the corresponding dual-channel wireless terminal 10 to a plurality of call forwarding gateways adjacent to the call forwarding gateway • 20-l~20-n in order to check the transmission/reception power between the call forwarding gateways and the dual-channel wireless terminal 10, and selects the call forwarding gateway having the highest transmission/reception power.
The line selection requesting means 408 requests the call forwarding gateway selected by the call forwarding gateway selecting means 406 to select the idle line from the lines of the payphones of the connected payphone group. When the call routing means 410 is notified that the call forwarding gateway selected by the call forwarding gateway selecting means 406 has selected the line of the idle state payphone, the call routing means 410 routes the speech path of the existing call forwarding gateway to the re-selected call forwarding gateway and the line of the payphone. Fig. 8 is a flowchart showing sequential steps of a method for wired/wireless call forwarding in accordance with yet another embodiment of the present invention. For convenience' sake, the call forwarding gateway and the line of the payphone which the dual-channel wireless terminal 10 is firstly connected to are referred to as a first call forwarding gateway and a first payphone line, and the call forwarding gateway and the line of the payphone re-selected due to reduction of the transmission/reception power are referred to as a second call forwarding gateway and a second payphone line.
When the speech path is formed between the dual-channel wireless terminal 10 and the recipient terminal according to the process of Fig. 4 or 5 and the call is made
(S301), the power sensing means of the first call forwarding gateway continuously senses the transmission/reception power between the dual-channel wireless terminal 10 and the first call forwarding gateway (S302). h the case that the transmission/reception power between the dual-channel wireless terminal 10 and the first call forwarding gateway is smaller than the designated value because of the movement of the dual-channel wireless terminal 10 or peripheral interference signals, the first- call forwarding gateway requests routing to the gateway exchange 400 (S303). That is, when the transmission/reception power between the dual- channel wireless terminal 10 and the first call forwarding gateway is reduced, the first call forwarding gateway decides that the dual-channel wireless terminal 10 exists on its communication radius boundary, and requests the gateway exchange 400 to route the call to the adjacent call forwarding gateway. Here, the first call forwarding gateway preferably transmits its ID number and the ID number of the dual-channel wireless terminal 10 to the gateway exchange 400.
The call forwardmg gateway selecting means 406 of the gateway exchange 400 receiving the routing request from the first call forwarding gateway confirms location information of the first call forwarding gateway by referring to the database 414 by the ID number of the first call forwarding gateway, and transmits information (ID number, etc.) of the dual-channel wireless terminal 10 to the plurality of adjacent call forwarding gateways, to check the transmission/reception power. When receiving the transmission/reception power between the dual-channel wireless terminal 10 and the call forwarding gateways from the call forwarding gateways, the call forwarding gateway selecting means 406 selects the call forwarding gateway having the highest transmission/reception power
(S304). The line selection requesting means 408 requests the second call forwarding gateway to select the line of the idle state payphone (S305).
The payphone selecting means of the second call forwarding gateway selects the line of the idle state payphone from the connected payphone group (S306), and notifies the result to the gateway exchange 400 (S307). Therefore, the call routing means 410 of the gateway exchange 400 accesses the second payphone line through the second call forwarding gateway (S308), and transmits routing information to the dual-channel wireless terminal 10 (S309). That is, the call routing means 410 transmits access information of the second call forwarding system to set the speech path. As a result, the speech path of the dual-channel wireless terminal 10 - second call forwarding gateway - second payphone line - recipient terminal is reset (S310), so that the user can continuously talk over the phone without experiencing call switching or feeling reset of the speech path (S311).
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalences of such metes and bounds are therefore intended to be embraced by the appended claims.
As discussed earlier, in accordance with the present invention, the communication module for performing wireless communication in a frequency band of 900MHz is mounted on the wireless terminal such as a cellular phone, PCS and PDA, and the call forwarding gateway is connected to the plurality of payphones for performing wireless communication in a frequency band of 900MHz. When the user attempts a call through the
900MHz band wireless communication function, the call attempt is transmitted to the
PSTN through the call forwarding gateway and the line of the payphone. Accordingly, the call attempts on the wireless network are forwarded into the wired network, to cut down call charges. In addition, when the wired terminal attempts a call to the dual-channel wireless terminal within the communication radius of the call forwarding gateway, the call attempt request of the caller is directly transmitted through the wired network, without passing through the wireless communication system, which reduces call charges of the caller.
Furthermore, the gateway exchange for managing states of the plurality of call forwarding gateways is installed. As a result, even if the user moves to another call forwarding gateway area during the call, he/she can continuously use the service without call switching.

Claims

What is claimed is:
1. A system for wired/wireless call forwarding, comprising: a dual-channel wireless terminal switched into a first mode and a second mode, for performing wireless communication in different frequency bands in each mode; a call forwarding gateway connected to a plurality of lines of payphones by wire for communicating with a PSTN, when the dual-channel wireless terminal is switched into the second mode, the call forwarding gateway performing wireless communication with the dual-channel wireless terminal within a designated radius, when the dual-channel wireless terminal is switched into the second mode to attempt a call within the designated radius, the call forwarding gateway attempting the call through the PSTN by selecting one of the lines of the payphones; and the PSTN receiving status information of the dual-channel wireless terminal from the call forwarding gateway, and transmitting call termination attempt to the call forwarding gateway including the dual-channel wireless terminal, when a wired telephone attempts the call termination to the dual-channel wireless terminal existing within the radius for communicating with the call forwarding gateway and switched into the second mode.
2. The system of claim 1, wherein the call forwarding gateway comprises: a payphone managing means for storing information of numbers and using states of each of the payphones of the payphone group within the designated distance from the call forwarding gateway in a database, and managing the information; a location information transmitting means for transmitting a number of the wireless terminal for communicating with the call forwarding gateway and an ID number of the call forwarding gateway to the PSTN so as to store the numbers; a payphone selecting means for selecting one idle state payphone from the payphone group, when the user of the wireless terminal switches the call mode of the wireless terminal into the designated frequency band and attempts a call; and a wireless-wired call exchanging means for connecting the call attempt of the wireless terminal to the PSTN through the payphone selected by the payphone selecting means.
3. The system of claim 2, wherein the call forwarding gateway further comprises: a power sensing means for sensing the intensity of transmission/reception power between the call forwarding gateway and the idle or call state dual-channel wireless termmal within the designated radius from the call forwarding gateway; and a warning tone sending means for generating a warning tone, when the transmission reception power between the dual-channel wireless terminal switched into the second mode and the call forwarding gateway proves to be smaller than a designated value by the power sensing means and thus the call is not available, when the transmission/reception power between the dual-channel wireless terminal making a call in the second mode and the call forwarding gateway is smaller than the designated value as the decision result of the power sensing means, or when the intensity of the signal of the dual-channel wireless terminal intended to be switched into the second mode is smaller than a designated value as the decision result of the power sensing means, or when another user intends to use the line of the payphone assigned to the dual-channel wireless terminal.
4. The system of claim 2, wherein the call forwarding gateway further comprises a wired-wireless call exchanging means for receiving a call attempt from the PSTN, and transmitting the call attempt to the wireless terminal, when the termination call is attempted to the wireless terminal.
5. The system of claim 2, wherein the call forwarding gateway further comprises a charging means for generating charging information based on call duration of the user of the wireless terminal, storing the charging information in a database, and periodically transmitting the stored charging information to the PSTN.
6. The system of claim 1, wherein a center frequency of the second mode for the wireless communication between the dual-channel wireless terminal and the call forwarding gateway is 900MHz.
7. The system of claim 1, wherein the dual-channel wireless terminal performs voice and data communication with a cellular wireless communication system through a base station in the first mode, and with the call forwarding gateway in the second mode in a frequency band having a center frequency of 900MHz.
8. A system for wired/wireless call forwarding, comprising: a dual-channel wireless terminal switched into a first mode and a second mode, for performing wireless communication in different frequency bands in each mode; a plurality of call forwarding gateways connected to a plurality of lines of payphones by wire for communicating with a PSTN, when the dual-channel wireless terminal is switched into the second mode, each of the call forwarding gateways performing wireless communication with the dual-channel wireless terminal within a designated radius, when the dual-channel wireless terminal is switched into the second mode to attempt a call within the designated radius, each of the call forwarding gateways attempting the call through the PSTN by selecting one of the lines of the payphones; a gateway exchange for transmitting information of the dual-channel wireless terminal to a plurality of call forwarding gateways adjacent to the call forwarding gateway in order to confirm the transmission/reception power between the call forwarding gateways and the dual-channel wireless terminal, receiving the transmission/reception power from each of the plurality of adjacent call forwarding gateways, and routing a speech path to the call forwarding gateway having the highest transmission/reception power, when the dual- channel wireless terminal receives a routing request from the call forwarding gateway performing voice and/or data communication; and the PSTN receiving status information of the dual-channel wireless terminal from the call forwarding gateway, and transmitting call termination attempt to the call forwarding gateway including the dual-channel wireless terminal, when a wired telephone attempts the call termination to the dual-channel wireless terminal existing within the radius for communicating with the call forwarding gateway and switched into the second mode.
9. The system of claim 8, wherein the gateway exchange comprises: a call forwarding gateway managing means for storing ID numbers and location information of the plurality of call forwarding gateways in a database, and managing the
LO numbers and information; a call forwarding gateway selecting means for transmitting information of the corresponding dual-channel wireless terminal to the plurality of call forwarding gateways adjacent to the call forwarding gateway so as to check the transmission/reception power between the dual-channel wireless terminal and the call forwarding gateways, and selecting the call forwarding gateway having the highest transmission/reception, power, when receiving a routing request from the call forwarding gateway; a line selection requesting means for requesting the call forwarding gateway selected by the call forwarding gateway selecting means to select an idle line from the lines of the payphones of the connected payphone group; and the call routing means for routing a speech path of the dual-channel wireless terminal connected to the call forwarding gateway to the re-selected call forwarding gateway and the line of the payphone, when a call routing means is notified that the call forwarding gateway selected by the call forwarding gateway selecting means has selected the line of the idle state payphone.
10. The system of claim 8, wherein the call forwarding gateway comprises: a payphone managing means for storing information of numbers and using states of each of the payphones of the payphone group within the designated distance from the call forwarding gateway in a database, and managing the information; a location information transmitting means for transmitting a number of the wireless terminal for communicating with the call forwarding gateway and an ID number of the call forwarding gateway to the PSTN so as to store the numbers; a payphone selecting means for selecting one idle state payphone from the payphone group, when the user of the wireless terminal switches the call mode of the wireless terminal into the designated frequency band and attempts a call; and a wireless-wired call exchanging means for connecting the call attempt of the wireless terminal to the PSTN through the payphone selected by the payphone selecting means.
11. The system of claim 10, wherein the call forwarding gateway further comprises: a power sensing means for sensing the intensity of transmission/reception power between the call forwarding gateway and the idle or call state dual-channel wireless terminal within the designated radius from the call forwarding gateway; and a warning tone sending means for generating a warning tone, when the transmission/reception power between the dual-channel wireless terminal switched into the second mode and the call forwarding gateway proves to be smaller than a designated value by the power sensing means and thus the call is not available, when the transmission/reception power between the dual-channel wireless terminal making a call in the second mode and the call forwarding gateway is smaller than the designated value as the decision result of the power sensing means, when the intensity of the signal of the dual- channel wireless terminal intended to be switched into the second mode is smaller than a designated value as the decision result of the power sensing means, or when another user intends to use the line of the payphone assigned to the dual-channel wireless terminal.
12. The system of claim 10, wherein the call forwarding gateway further comprises a wired-wireless call exchanging means for receiving a call attempt from the PSTN, and transmitting the call attempt to the wireless terminal, when the termination call is attempted to the wireless terminal.
13. The system of claim 10, wherein the call forwarding gateway further comprises a charging means for generating charging information based on call duration of the user of the wireless terminal, storing the charging information in a database, and periodically transmitting the stored charging information to the PSTN.
14. The system of claim 8, wherein a center frequency of the second mode for the wireless communication between the dual-channel wireless terminal and the call forwarding gateway is 900MHz.
15. The system of claim 8, wherein the dual-channel wireless terminal performs voice and data communication with a cellular wireless communication system through a base station in the first mode, and with the call forwarding gateway in the second mode in a frequency band having a center frequency of 900MHz.
16. A method for wired/wireless call forwarding in a call forwarding system, the call forwarding system connected to a PSTN through a payphone group including a plurality of payphones, for performing wireless communication with a wireless terminal in a designated frequency band, and transmitting a call attempt of the wireless terminal to the PSTN through a line of the payphone, the method comprising: selecting one idle state payphone from the payphone group, when the user of the wireless terminal switches a call mode of the wireless terminal into the designated frequency band, and inputs a number of a recipient terminal to attempt a call; and transmitting the call attempt request of the wireless terminal to the PSTN through the selected payphone, and forming a speech path between the wireless terminal and the PSTN.
17. The method of claim 16, further comprising a step for authenticating the user of the wireless terminal after attempting the call and before selecting the idle state payphone.
18. The method of claim 16, further comprising a step for confirming recipient information in the PSTN, transmitting a ring signal to the recipient terminal, generating charging information based on call duration when the call starts between the wireless terminal and the recipient terminal, and transmitting the charging information to the PSTN, after the step for forming the speech path between the wireless terminal and the PSTN.
19. The method of claim 16, wherein the designated frequency band has a center frequency of 900MHz.
20. The method of claim 16, wherein the wireless terminal is operated in two communication modes, for performing communication with the wireless communication system through a base station, and performing data communication in a frequency band having a center frequency of 900MHz.
21. A method for wired/wireless call forwarding in a call forwarding system, the call forwarding system comprising a call forwarding gateway connected to a PSTN through a payphone group including a plurality of payphones, for performing wireless communication with a wireless terminal in a designated frequency band, and transmitting a call attempt of the wireless terminal through the PSTN, the method comprising: continuously transmitting a number of the wireless terminal and an ID number of the call forwarding gateway in which the wireless terminal is located to the PSTN; confirming user information of the wireless terminal, when a caller terminal attempts a call to the wireless terminal through the PSTN; extracting the call forwarding gateway in which the wireless terminal is located; selecting one idle state payphone from the payphone group included in the call forwarding gateway; transmitting the call attempt request of the wireless terminal to the call forwarding gateway through the selected payphone; and transmitting a ring signal to the wireless terminal.
22. The method of claim 21, further comprising a step for generating charging information based on call duration when the call starts between the caller terminal and the wireless terminal, and transmitting the charging information to a PSTN provider and a wireless communication system provider, after the step for transmitting the ring signal to the wireless terminal.
23. The method of claim 21, wherein the designated frequency band has a center frequency of 900MHz.
24. The method of claim 21, wherein the wireless terminal performs communication with the wireless communication system through a base station, and performs data communication with the call forwarding gateway in a frequency band having a center frequency of 900MHz.
25. A dual-channel wireless terminal connected to a wireless communication system through a base station and a PSTN through a payphone, comprising: a first communication network interface for communicating with the wireless communication system in a first frequency band; a second communication network interface for performing wireless communication in a second frequency band excluding the first frequency band; and a channel changing means for selecting a communication mode using one of the first frequency band and the second frequency band.
26. The dual-channel wireless terminal of claim 25, wherein the second frequency band has a center frequency of 900MHz.
27. A method for wired/wireless call forwarding in a call forwarding system, the call forwarding system comprising a dual-channel wireless terminal for performing wireless communication in different frequency bands, a plurality of call forwarding gateways connected to a PSTN through a payphone group including a plurality of payphones, for performing wireless communication with the dual-channel wireless terminal in a designated frequency band, and transmitting a call attempt of the dual- channel wireless terminal to the PSTN through a line of the payphone, and a gateway exchange receiving a routing request from the call forwarding gateway, and routing a speech path according to the transmission/reception power between a plurality of call forwarding gateways adjacent to the call forwarding gateway and the dual-channel wireless terminal, the method comprising: forming a speech path between the dual-channel wireless terminal and a recipient terminal; continuously sensing, at a first call forwarding gateway, the transmission/reception power between the first call forwarding gateway . and the dual- channel wireless terminal, and requesting routing to the gateway exchange when the transmission/reception power is smaller than a designated value; confirming, at the gateway exchange, location information of the first call forwarding gateway, and requesting the plurality of adjacent call forwarding gateways to confirm the transmission/reception power between the call forwarding gateways and the dual-channel wireless terminal; receiving the transmission/reception power between the call forwarding gateways adjacent to the first call forwarding gateway and the dual-channel wireless terminal from the call forwarding gateways, and selecting a second call forwarding gateway having the highest transmission/reception power; requesting the second call forwarding gateway to select a line of an idle state payphone; connecting the gateway exchange to the line of the payphone through the second call forwarding gateway, when the second call forwarding gateway selects the line of the idle state payphone and notifies the result to the gateway exchange, and transmitting routing information to the dual-channel wireless terminal; and resetting the speech path among the dual-channel wireless termmal, the second call forwarding gateway, the line of the payphone and the recipient terminal.
28. The method of claim 27, wherein the step for requesting routing to the gateway exchange at the first call forwarding gateway further comprises a step for transmitting an ID number of the first call forwarding gateway and an ID number of the dual-channel wireless terminal.
29. The method of claim 27, wherein the step for forming the speech path comprises the steps of: selecting one idle state payphone from the payphone group, when the user of the wireless terminal switches a call mode of the wireless terminal into the designated frequency band, and inputs a number of the recipient terminal to attempt a call; and transmitting the call attempt request of the wireless terminal to the PSTN through the selected payphone, and forming the speech path between the wireless terminal and the PSTN.
30. The method of claim 27, wherein the step for forming the speech path comprises: continuously transmitting a number of the wireless terminal and an ID number of the call forwarding gateway in which the wireless terminal is located to the PSTN; confirming user information of the wireless terminal, when a caller terminal attempts a call to the wireless terminal through the PSTN; extracting the call forwarding gateway in which the wireless terminal is located; selecting one idle state payphone from the payphone group included in the call forwarding gateway; transmitting the call attempt request of the wireless terminal to the call forwarding gateway through the selected payphone; and transmitting a ring signal to the wireless terminal.
PCT/KR2003/001761 2002-09-06 2003-08-29 System and method for wired/wireless call exchanging and dual-channel wireless terminal therefor WO2004023771A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003256123A AU2003256123A1 (en) 2002-09-06 2003-08-29 System and method for wired/wireless call exchanging and dual-channel wireless terminal therefor

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2002-0053901 2002-09-06
KR20020053901 2002-09-06
KR10-2003-0021555A KR100521989B1 (en) 2002-09-06 2003-04-07 System and Method for Wired/Wireless Call Exchanging and Dual-Channel Wireless Terminal Therefor
KR10-2003-0021555 2003-04-07

Publications (1)

Publication Number Publication Date
WO2004023771A1 true WO2004023771A1 (en) 2004-03-18

Family

ID=31980692

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2003/001761 WO2004023771A1 (en) 2002-09-06 2003-08-29 System and method for wired/wireless call exchanging and dual-channel wireless terminal therefor

Country Status (2)

Country Link
AU (1) AU2003256123A1 (en)
WO (1) WO2004023771A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011133940A2 (en) * 2010-04-22 2011-10-27 Belkin International, Inc. System and method for receiving and placing telephone calls

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR19980061387A (en) * 1996-12-31 1998-10-07 배순훈 Performance tester and method of screen measuring device
KR20000027438A (en) * 1998-10-28 2000-05-15 원종국 Mobile phone used as city phone as well as pcs phone
KR20030032776A (en) * 2001-10-20 2003-04-26 인포뱅크 주식회사 System and Method for Wire/Wireless Call Exchanging and Wire/Wireless Multi-Functional Terminal Therefor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR19980061387A (en) * 1996-12-31 1998-10-07 배순훈 Performance tester and method of screen measuring device
KR20000027438A (en) * 1998-10-28 2000-05-15 원종국 Mobile phone used as city phone as well as pcs phone
KR20030032776A (en) * 2001-10-20 2003-04-26 인포뱅크 주식회사 System and Method for Wire/Wireless Call Exchanging and Wire/Wireless Multi-Functional Terminal Therefor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011133940A2 (en) * 2010-04-22 2011-10-27 Belkin International, Inc. System and method for receiving and placing telephone calls
WO2011133940A3 (en) * 2010-04-22 2012-01-05 Belkin International, Inc. System and method for receiving and placing telephone calls

Also Published As

Publication number Publication date
AU2003256123A1 (en) 2004-03-29

Similar Documents

Publication Publication Date Title
AU2004202077B2 (en) Complex wireless service arrangement using wired or wireless communication systems
EP0705522B1 (en) Multinetwork terminal
US6775546B1 (en) Mobile telephone system
JP2952857B2 (en) Mobile communication system and control method therefor
JP2001523422A (en) Cell Selection Based on User Profile in Cellular Wireless System
US7043248B2 (en) System and method for providing telecommunication services
GB2234649A (en) Personal communications systems
CA2332030A1 (en) System and method for delivering a call for a mobile station using either a wireless network or a wireline network
US6522896B2 (en) Antenna diversity base station for transmission of unidirectional channels and corresponding method of transmission of a unidirectional channel by a base station
JP4749125B2 (en) Mobile phone with repeater function
EP1110421B1 (en) Home zone extension phone service
KR100556464B1 (en) method for call forwarding in mobile telecommunication system
JP2003101474A (en) Mobile communication system
WO2004023771A1 (en) System and method for wired/wireless call exchanging and dual-channel wireless terminal therefor
KR100521989B1 (en) System and Method for Wired/Wireless Call Exchanging and Dual-Channel Wireless Terminal Therefor
JP2000349871A (en) Composite portable phone
JP3282658B2 (en) Mode switching method for mobile phones
KR100233912B1 (en) Method for connecting call with charged phone number in a switching system
KR100617542B1 (en) mobile communication terminal having a transferring and receiving SMS identification function and controlling method therefore
KR100489946B1 (en) Auto Re-Calling Control Method At The Internal wired,wireless network Co-Service System
KR100507804B1 (en) Location Register Method At The Internal wired, wireless network Co-Service System
JPH10224844A (en) Radio communication equipment
JPH07336761A (en) Mobile communication system
JP2734376B2 (en) Cellular phone connection control method, device and method
JP3715539B2 (en) Location information notification system for mobile terminals

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP