WO2010086807A1

WO2010086807A1 - Mobile phone call to pstn conversion system

Info

Publication number: WO2010086807A1
Application number: PCT/IB2010/050373
Authority: WO
Inventors: Benjamin Maytal; Carmi Nachman Bogot
Original assignee: Benjamin Maytal; Carmi Nachman Bogot
Priority date: 2009-01-29
Filing date: 2010-01-27
Publication date: 2010-08-05

Abstract

The present invention will allow easy and convenient connectivity in the home and in the office between the mobile phone and the PSTN service. The mobile phone will be effectively emulating a cordless phone. The user will be able to send and receive PSTN calls from his mobile phone while still being able to make mobile phone calls. The present invention will also allow easy connection to mobile phones for multiple applications, such as for making payments, gaining access, and participation in loyalty programs. The present invention will also allow alternative access for data services on the mobile phone. This alternative access will be beneficial to the end user since it will lower cost and it will optionally be beneficial to the mobile service provider allowing them to route data traffic over a more efficient network.

Description

MOBILE PHONE CALL TO PSTN CONVERSION SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit from U.S. Provisional Patent Application No. 61/206,152, filed January 29, 2009, which is hereby incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

[0002] There are several solutions for low cost calls from mobile phones - however, none of them offers a natural call from a standard phone.

[0003] There are several VOIP packages (e.g., Fring) from mobile phones - they typically require phones with Wi-Fi or at least Smart Phones. These will be VOIP calls over the internet - not PSTN calls.

[0004] There were several attempts to have low cost mobile calls through Bluetooth. The most famous one was the Bluephone by British Telecom. They all required using special phones ( e.g. a Bluephone)

[0005] Also, Femtocells, small local, indoor base stations are being offered today. They offer better coverage or even lower costs for the operator. They do not offer connectivity to the PSTN and are connected to the mobile network.

[0006] Several patents describing conversion from mobile calls to PSTN were detected.

US5675629, US2002132582, GB2371717, US6035193, DE4307966, US2005064853.

However, they are either based on Wi-Fi or Bluetooth in the mobile phones and special software, or special mobile phones.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0008] Figure 1 describes a first embodiment of the system. A GSM to PSTN system 2 is connected to phone jack 1 and to a standard phone 3 through a phone jack and through GSM to mobile phone 4. Mobile phone 4 can also be connected over GSM to the neighborhood base station 5.

[0009] Figure 2 describes a second embodiment of the system. A GSM to PSTN system 2 is connected to phone jack 1 and to a standard phone 3 through a phone jack and through

GSM to mobile phone 4. It is also connected through GSM at a different frequency range to neighborhood mobile base station 5.

[0010] Figure 3 describes a GSM to PSTN system. Home base station 21 is connected to

PSTN interface 22 and via GSM to home mobile phones 3. Frequency blocking device 24 is transmitting signals to home mobile phones 3. Device 25 is a mobile network listening device listening to mobile phone 3 and neighborhood base station 5.

[0011] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

[0012] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0013] GSM mobile phones can connect in 4 frequency ranges - 850MHz, 900MHz, 1800MHz, and 1900MHz. In each of these ranges there is a specific range for download frequencies ( from the base station to the mobile phone) and upload ( from mobile phone to base station). Most mobile phones can connect to all frequencies, however, in each geography, only two frequency ranges are licensed to mobile operators - in the USA and rest of America, these are the 850MHz and 1900 MHz ranges, and in the rest of the world the 900 and 1800 ranges. The mobile phones are capable of automatically switching from one range to the other, depending on mobile network conditions. The present invention will describe how unlicensed GSM frequencies can be used at home for converting costly GSM calls to PSTN calls for standard mobile phones with no need for any change or software download.

[0014] Figure 3 describes the GSM to PSTN system. It incorporates a small base station 21 ( capable of a small number of calls, potentially only one). It will transmit at the unlicensed GSM frequencies at the given geography. For example, in the US it will transmit in 900MHz. It will transmit at an intensity much stronger than the neighborhood GSM signal. It is connected to a PSTN interface., which will be able to convert mobile phone call to a PSTN call and vice versa. A call start is converted to a PSTN off hook signal , target numbers to DTMF signals and GSM data to PSTN signals. The GSM to PSTN system will also incorporate a frequency blocking device 24. Most mobile phones will not switch from their own provider network( programmed as preferred network in their mobile phone SIM) network as long as it has a good quality signal. After a first connection was made, most mobile phones will reconnect to the non-preferred network The frequency blocking device will interfere and block the neighborhood base station GSM signals, which will cause the mobile phone to switch to the home frequency. For example, in the US the neighborhood base station GSM frequency will be in the 1900 range and the home frequency in the 900 range. The frequency blocking device can be implemented as either a Faraday Cage or a jammer. A faraday cage is a system built of materials preventing radiation to penetrate the system or leave the system. A user will be asked to put his mobile phone in the system when entering home. An alternative is to have a jammer - a device which will transmit interfering signals at a given frequency, which can block the frequencies of the neighborhood base station and cause the mobile phone to connect over the home frequency to the home base station 21. Optionally, the home base station 21 can transmit at the same frequency range and the mobile phone will still connect to it , because when in the Faraday cage there is no other option and the jammer can be strong enough to block the neighborhood base station GSM network, but not the strong home network.

[0015] Under the present invention, when at home, GSM to PSTN system 2 will take over the house mobile phone. A user call, either dialed by the user or selected from the Address Book, will be converted to PSTN call. As described in figure 1 GSM to PSTN the GSM to PSTN system 2 is able to transmit over standard GSM frequency ranges - 800MHz, 900MHz, 1800MHz, 1900MHz. Typically most mobile phones are able to transmit on all frequencies. Typically a mobile phone will connect to the strongest base station. The GSM to PSTN system 2 serve as the house base station and will transmit over a GSM frequency which is unlicensed in this specific country ( and therefore not used as a GSM frequency) for example, 900 MHz in the US. Alternatively, it can transmit in the licensed frequency range if it is allowed to transmit unlicensed indoors or through a provider which has licensed frequencies, which can be in a very limited range. Although the frequencies discussed above are for GSM system, the same concept can hold for any mobile phone network standard with different operating frequencies in different geographies.

[0016] The system 2 will either be pre-programmed for a certain frequency band or will recognize the bands the mobile transmission is being carried out and will pick another range, unlicensed in this country. In case the provider supplying the system has licensed a certain range than it will transmit within this range and at channels other than neighboring channels. In case it is allowed to transmit indoors at the mobile operator range then the transmission will be at channels different than the neighborhood GSM channel.

[0017] System 2 may listen through device 25 to the neighborhood base station and will transmit at a signal strength larger than the neighborhood base station.

[0018] Mobile phones may be programmed to prefer their own network - even if there is a stronger signal from another base station, the phone will remain connected to its own network base station. 3G phones may be programmed to prefer 3G base stations. Often, mobile phones are also programmed to prefer base stations they have connected to recently. [0019] To allow connection to the home base station 2, several techniques can be used. [0020] Another alternative is to have an application installed in mobile phone used at home (When a user wishes to use the GSM to PSTN system , the user may press the application Icon and the application will select the home networks from the list of optional networks and connect to it.

[0021] Another alternative is to ask the user to put his phone SIM inside the GSM to PSTN 2 when the user is in the registration process The SIM will be programmed such that the home network will be considered the preferred network.

[0022] Prior to operation the GSM to PSTN system 2 needs to be programmed to recognize the phones in the house. By pressing a bottom in the GSM to PSTN GSM to PSTN system 2 and dialing a specific number used for registration, the mobile phone number will be registered to the particular system. The GSM to PSTN system 2 will act as a base station that the user's mobile phone(s) will be connected to. The mobile phone(s) will switch automatically to system 2 due to its stronger signal after one of the methods of forcing a connection to it described above was taken.

[0023] System 2 may have 3 operation modes with respect to the in house mobile phones. First, it may not be transmitting at all, second, it may be transmitting and connected to the mobile phone, and third, it maybe transmitting and not connected to a specific mobile phone .Under a first embodiment of the invention the in house mobile phones remain connected to the neighborhood base station . The SYSTEM 2 is either inactive or will not recognize and remain disconnected from the in house mobile phone. Mobile phone calls to the phones as well as in and out SMS or data can take place. System 2 through network listening device 25 will recognize the frequency used by the neighborhood base station 5 and will keep listening to it and to the corresponding frequency used by the mobile phone communicating with base station 5.

[0024] When a user will dial a number or select a number to dial and press send on his mobile phone, a request for call service will be issued by the mobile phone. It will be recognized by network listening device 25 inside the GSM to PSTN system 2 , which will go into action and will start transmitting a strong GSM signal. Potentially the jammer can also be activated at this time. The connection of the mobile phone 3 to base station 5 will stop. A connection between the mobile phone 3 and system 2 will be established. A PSTN call will be initiated over phone Jack 1. An off hook signal will be issued and the call will be established with the target number. Voice samples will be converted from PSTN signaling to mobile phone samples. To identify the mobile phone to the receiving side, PSTN DTMF signaling for the mobile ID will be sent, preceding the DTMF for the target number. The PSTN provider line cards or equipment will be able to extract this number and pass it (instead of the house PSTN number) to the other side.

[0025] When a call comes in via PSTN, it will be recognized by the GSM to PSTN system 2 and the call will be answered. The GSM to PSTN system 2 will act as a base station and will try to establish connections with the phones in the authorized list. Due to the fact that the signal from the GSM to PSTN system 2 will be stronger that other available signals, this will cause the phones at home to connect to it, rather than to the external standard mobile base station. Once a single phone connects, other attempts at connections will be stopped, and a call session will take place. When the user hangs the mobile phone up the GSM to PSTN system 2 will cause a hang up on the PSTN side.

[0026] GSM to PSTN system 2 , the basic system will support only one call, therefore it can be implemented using of the shelf low cost GSM mobile handset devices , which can be reprogrammed to act as a base station

[0027] Devices in adjacent apartments can potentially interfere with each other. Each system will recognize transmission by an adjacent device . The system can then broadcast at a different TDMA (Time) slot or at a different frequency channel.

[0028] Under another embodiment of the invention described in figure 2 the GSM to PSTN system 12 will, in addition to the GSM to PSTN system functionality, also perform mobile phone emulation. Thus, system 12 will maintain also a GSM connection under the local frequency range to the neighborhood base station 5.

[0029] In this case, the system 12 will keep transmitting all the time control signals and keep the GSM connection with the mobile phone 4 (there may be more than one) over the in- house frequency. The system 12 will also be connected to the GSM network. It will receive all SIM information from the mobile phones 4 and transmit it to base station 5. It will appear to the base station as being connected to the house mobile phones. The system 12 will not connect to other mobile phones (not in the house list). These will still be connected to the regular GSM network.

[0030] When a call will come to the house mobile phones, it will be received by system 12 over the neighborhood base station and will transfer the call to the house phones over the established house network, at another frequency. When an SMS is being made or any other session which wishes to go over the neighborhood GSM network, it will be transmitted to system 12 which will decide if to transmit it over PSTN or GSM, and if on GSM, system 12 will send it over the local neighborhood.

[0031] Under another aspect of the invention, the house mobile phone subscribers will ask for another SIM and will plug it inside system 12, which will than establish communication with the neighborhood base station .

[0032] For set up and received PSTN calls, system 12 will behave as system 2 described earlier. System 12 will also transmit in frequencies as described for system 2. [0033] When the mobile phone 4 will make a call, it will go to the GSM to PSTN system

12.The GSM to PSTN system 12 will decide if this call needs to be transmitted over the

PSTN network or over the mobile network. If the call was targeted to a ^number, it will be sent over the GSM network. The system 12 can also decide depending on the number and time of the day to send the call over the GSM network to base station 5.

[0034] When a call comes in over PSTN it will be transmitted by system 12 to mobile phone 4.

[0035] If more than one mobile phone was introduced to the system, the call will be sent according to priority to a first number.

[0036] When a GSM call is being received by the GSM to PSTN system 12, it will be transmitted by it to the appropriate phone.

[0037] GSM to PSTN system 12 may support only one in house call or more. It is possible that there are more phones at home than the number of calls supported and that there be more calls coming in than supported. After the system 12 has established an in house GSM connection with the number mobile phones it can support simultaneously, it will stop connecting with the other phones which will switch back to the neighborhood GSM base station.

[0038] It will be appreciated that the present invention requires no change or additional software on the mobile phone. Under another embodiment of the invention System 2 or 12 will send control signals to the phone with the local network identity.

[0039] Under another aspect of the invention, if the user is leaving the house in the midst of the call, the system 2 or 12will keep the connection with the other side over PSTN or mobile. It will recognize that the connection was lost and will initiate a mobile call using one of the house SIM identities and will transfer the call once the user has answered the call.

[0040] If a user is entering the house then the call will be continued over the mobile network. Under another aspect of the invention, the bridging systems will not be connected to

PSTN but to a LAN, or wireless LAN. The call transmission will therefore be not a simple voice transmission over PSTN but a VOIP call. Each mobile phone may be assigned an office extension number and the telephony connection may be made through an office VOIP PBX.

The bridging systems may also incorporate all PBX supported features. [0041] Under another aspect of the invention, if the user is leaving the house then the call will be kept in the mobile phone which will initiate a call to the other party.

[0042] Under another aspect of the invention, to implement the base station functionality of system 2, a low cost handset mobile component will be used. It will be programmed to execute layer 2 and layer 3 of GSM communication for a base station, and not a mobile phone. This will enable a low cost implementation of system 2.

[0043] Under another aspect of the invention_^ the home base station will be a 3G mobile , not GSM. The home base station will select frequencies not used by a neighboring base station. In order to avoid collision between neighboring home base stations, each home base station will detect the frequency used by home base stations. It will also detect the CDMA code used by the other system and will use another code to transmit. Under another aspect of the invention, system 2 will not be used to pass phone calls. It will be used to identify the mobile phone SIM number ( also known as IMSI) , as a mean for personal identification used by the user for payment or control access purposes.

[0044] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

CLAIMSWhat is claimed is:

1. An indoor telephone exchange comprising: a base station to provide connectivity for at least one cellular telephone over a first cellular telephony frequency range supported by said at least one cellular telephone but not in use by a local cellular network; and a telephony interface to connect said base station with a non-cellular telephony network.

2. The exchange according to claim 1 and wherein said non-cellular telephony network is a PSTN (plain simple telephone network).

3. The exchange according to claim 1 and wherein said non-cellular telephony network is a VOIP (voice over internet protocol) LAN (local area network).

4. The exchange according to claim 1 wherein the system remains inactive until it recognizes that a close mobile phone is trying to make a call.

5. The exchange according to claim 3 and also comprising: a cellular telephone proxy unit to communicate with said at least one cellular telephone to said local cellular network over a second cellular telephony frequency generally in use by said local cellular network and with said cellular telephone via said base station over said first frequency, wherein said cellular telephone proxy unit represents itself as said cellular telephone to said local cellular network.

6. The exchange according to claim 1 and wherein said local cellular network is a GSM network.

7. The exchange according to claim 1 and also comprising a Faraday cage to receive said cellular telephone and to disconnect it from said local cellular network.

8. A method for an indoor telephone exchange, the method comprising: enabling a cellular telephone, which uses a first cellular telephone frequency for communicating via a local cellular telephone network, to use a second cellular telephone frequency, also supported by said cellular telephone.

9. The method according to claim 8 and also comprising: transmitting and receiving identification details between said at least one cellular telephone and said local cellular network, wherein said local cellular network is accessed over a second cellular telephony frequency range via a cellular telephone proxy unit, wherein said second frequency range is generally supported by said local cellular network.

10. The method according to claim 9 and wherein said cellular telephone proxy unit represents itself as said at least one cellular telephone when communicating with said local cellular network.

11. The method according to claim 9 and also comprising: transmitting and receiving at least one of voice and data between said at least one cellular telephone and said local cellular network, wherein said local cellular network is accessed via said cellular telephone proxy unit.

12. The method according to claim 12 and also comprising: receiving outgoing SMS messages from said cellular telephone; and forwarding said SMS messages to said local cellular network via said cellular telephone proxy unit.

13. The method according to claim 11 and also comprising: receiving incoming telephone calls from said PSTN; and connecting said telephone calls with said cellular telephone.

14. The method according to claim 11 and also comprising: using a Faraday cage to disconnect said cellular telephone from said local cellular network; and enabling said cellular telephone to connect to said first cellular telephony frequency range after said disconnection

15. A cellular telephone proxy unit comprising: a call interface unit to transmit and receive at least one of voice and data between a local cellular network and a cellular telephone accessed through a base station, wherein said cellular telephone is capable of communicating with said base station via a different frequency range than that used by said local cellular network; and a security interface unit to transmit and receive at least identification details with said local cellular network and said cellular telephone.

16. The unit according to claim 15 and wherein a source for said identification details is a GSM SIM located on said cellular telephone.

17. A system comprising: a home base station working at a certain frequency; and a jammer to send jamming signals at other mobile network frequencies.

18. A system comprising: an in-building base station operative in 3 G CDMA; and neighboring in-building base stations, wherein each said in-building base station comprises a unit to select a CDMA code not used by said neighboring in-building base stations.

19. An in-building base station using frequencies different than those used by the local base stations, said base station used to identify the mobile phone of the user.