Patent Publication Number: US-2007099613-A1

Title: Method and system for forwarding calls to a secondary wireless network using a multi-protocol wireless device

Description:
FIELD OF THE INVENTION  
      This invention relates generally to communication systems, and more particularly to a method and system for forwarding calls using a multi-protocol wireless device and network.  
     BACKGROUND OF THE INVENTION  
      In a cellular phone system using multi-protocol handsets (iDEN/CDMA for example), determining which network to use for voice calls at any given time can involve additional cost and complexity. The typical method as illustrated in the system  10   FIG. 1  would be to assign multiple phantom id&#39;s (or phone numbers)  15  and  17  to a multi-protocol handset  18  for use on each of its supported protocols  14  and  16  respectively. Then a separate infrastructure switch  16  that owns the users real (public) phone number  12  monitors signal quality on each of the available protocols. When a call is placed to the users real phone number  12 , the infrastructure switch  13  will determine which protocol  14  or  16  (and therefore phantom id  15  or  17 ) is best to use, and will route the call appropriately through the chosen protocol. The extra infrastructure switch  13  that monitors signal quality on the various protocols and routes the call adds extra cost to the network and system  10 , and requires coordination of multiple operators to route calls.  
      WLAN phones can use a system similar to that described above in which a PBX routes calls between an internal wireless network and an external phone provider, but no known systems use the methods described herein in a handset to achieve similar functionality.  
     SUMMARY OF THE INVENTION  
      Embodiments in accordance with the present invention can use methods in a handset or mobile wireless device to determine which network is most appropriate for handling a call at any given time. The wireless device can then use standard network call forwarding methods to route calls to the correct real or phantom phone number associated with the wireless device. The handset can determine which protocol is most appropriate using various methods that can be analyzed by the handset, including signal quality, location within the network (using GPS or cell tower identifiers), and costs associated with using the various networks available.  
      In a first embodiment of the present invention, a multi-protocol phone call routing system can include a wireless transceiver capable of operating on a primary wireless network and at least one alternative wireless network, and a processor coupled to the wireless transceiver. The primary wireless network can be an IDEN network and an alternative wireless network can be a CDMA network although the embodiments herein are certainly not limited thereto and can include other networks within contemplation of the scope of the claims. For example, the primary network can be one among an iDEN, UMTS, GSM, or CDMA wireless networks and the alternative wireless network can be one among IDEN, UMTS, GSM, or CDMA wireless networks. The transceiver can be programmed to monitor signal quality (such as signal strength or bit error rate), location or cost on the primary wireless network or on the at least one alternative wireless network and request to carry traffic on the primary wireless network or the at least one alternative wireless network by the wireless transceiver based on analysis at the wireless transceiver of the signal quality or location or cost when using the primary wireless network or the at least one alternative wireless network. The system can be further programmed to monitor signal quality on the primary wireless network, power-up an alternative wireless network transceiver portion of the wireless transceiver if a signal quality on the primary wireless network falls below a predetermined threshold, and request to forward calls to a primary wireless network transceiver portion of the wireless transceiver to the alternative wireless network transceiver portion. The system can be further programmed to request canceling forwarded calls to the alternative wireless network transceiver portion when the signal quality on the primary wireless network reaches above the predetermined threshold and to transfer calls back to the primary wireless network when the signal quality on the primary wireless network reaches above the predetermined threshold and power down the alternative wireless network transceiver. Note, the system can requests to forward calls to the alternative wireless network transceiver portion by transferring calls to a phantom phone number.  
      In a second embodiment of the present invention, a multi-protocol cellular phone can include a wireless transceiver capable of operating on a primary wireless network or an alternative wireless network, and a processor coupled to the wireless transceiver. The transceiver can be programmed to power-up the wireless transceiver on the primary wireless network, monitor signal quality on the primary wireless network, power-up the wireless transceiver on the alternative wireless network if the wireless transceiver detects a signal quality below a predetermined threshold on the primary wireless network, and request to forward calls to the primary wireless network to a phantom phone number on the alternative wireless network when the primary wireless network falls below a predetermined threshold using internet traffic through the alternative wireless network. The multi-protocol cellular phone can be further programmed to cancel the request to forward calls to the phantom phone number when the wireless transceiver detects a signal quality above the predetermined threshold on the primary wireless network. The multi-protocol cellular phone can be further programmed to power-down the wireless transceiver on the alternative wireless network once the wireless transceiver detects the signal quality above the predetermined threshold on the primary wireless network. Although the primary and secondary networks can be any number of networks, one example can have an iDEN wireless network for the primary wireless network and a CDMA wireless network for the alternative wireless network.  
      In a third embodiment of the present invention, a method of forwarding calls to a secondary wireless network using a mobile multi-protocol wireless device can include the steps at the multi-protocol wireless device of monitoring a signal quality on a primary wireless network, requesting to carry traffic on an alternative wireless network if the signal quality on the primary wireless network falls below a predetermined threshold, and requesting to forward calls to the primary wireless network to the alternative wireless network (to a phantom phone number, for example) when the primary wireless network falls below the predetermined threshold. The request to forward calls to the phantom phone number on the alternative wireless network can be done using internet traffic on the alternative wireless network. The method can further include the step of requesting to cancel forwarding calls to the alternative wireless network when the signal quality on the primary wireless network reaches above the predetermined threshold. The method can further include the steps of powering-up an alternative wireless network transceiver when the signal quality (such as signal strength or bit error rate) on the primary wireless network falls below the predetermined threshold and powering down the alternative wireless network transceiver when the signal quality on the primary wireless network reaches above the predetermined threshold. The method can further include the step of powering-up the multi-protocol wireless device on the primary wireless network and camping on the primary wireless network. The method can further include requesting to forward calls to the primary wireless network to the alternative wireless network when the primary wireless network analyzes a cost factor or a location and determines a predetermined cost advantage for switching to the alternative wireless network.  
      Other embodiments, when configured in accordance with the inventive arrangements disclosed herein, can include a system for performing and a machine readable storage for causing a machine to perform the various processes and methods disclosed herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an illustration of an existing system using an infrastructure switch to switch between communication protocols.  
       FIG. 2  is a multi-protocol phone call routing system having a wireless transceiver capable of operating on a primary wireless network or at least one alternative wireless network in accordance with an embodiment of the present invention.  
       FIG. 3  is the multi-protocol phone call routing system of  FIG. 1  illustrating the routing of a phone call to a secondary network using a phantom phone number when a signal quality is below a predetermined threshold in accordance with an embodiment of the present invention.  
       FIG. 4  is a flow chart illustrating a method of forwarding calls to a secondary wireless network using a mobile multi-protocol wireless in accordance with an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      While the specification concludes with claims defining the features of embodiments of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the figures, in which like reference numerals are carried forward.  
      Referring to  FIGS. 2 and 3 , a dual protocol handset or mobile radio  22  in a multi-protocol phone call routing system  20  can have the real public phone number  27  assigned to one of its protocols (using a primary network  24  such as an IDEN network for example), and a phantom phone number  21  assigned to each of the alternate protocols (using an secondary or alternate network  32  such as a CDMA network for example). Under normal conditions, the mobile radio  22  will use the primary network  24  and a public switch  26  to communicate with other networks  30  throughout the world. In the case of an iDEN network as the primary network  24 , when the iDEN modem in the handset or mobile radio  22  determines through signal quality (using signal strength, bit error rate, or other methods) that it can no longer provide service, the mobile radio can generate a call forwarding request  29  to send any calls received at the real public phone number to the phantom phone number used by the CDMA modem (and the alternate or secondary network  32 ). The handset or mobile radio  22  can send the call forwarding request by various methods including using a control channel in the primary network or using packet data traffic (through the internet) on either the primary or alternate protocol. Then, the mobile radio  22  routes calls via the phantom phone number  21  using the alternate or secondary network  32 .  
      When the handset determines that the primary network  24  is now capable of handling voice traffic again, it will use one of the available methods to send a request to the network to cancel call forwarding. The primary public phone number will then ring through primary carrier again.  
      Referring to  FIG. 4 , a flow chart illustrating a method  40  of forwarding calls to a secondary wireless network using a mobile multi-protocol wireless device can include the step  42  of powering-up the multi-protocol wireless device on the primary wireless network and camping on the primary wireless network. The multi-protocol wireless device can monitor a signal quality on a primary wireless network at step  44 , request to carry traffic on an alternative wireless network if the signal quality on the primary wireless network falls below a predetermined threshold at step  46 , and request to forward calls to the primary wireless network to the alternative wireless network (to a phantom phone number, for example) when the primary wireless network falls below the predetermined threshold at step  48 . The request to forward calls to the phantom phone number on the alternative wireless network can be done using internet traffic on the alternative wireless network. The method  40  can further include the step  50  of powering-up an alternative wireless network transceiver when the signal quality (such as signal strength or bit error rate) on the primary wireless network falls below the predetermined threshold. The method  40  can further include the optional step  52  of requesting to forward calls to the primary wireless network to the alternative wireless network when the primary wireless network analyzes a cost factor or a location and determines a predetermined cost advantage for switching to the alternative wireless network. The method  40  can further include the step  54  of requesting to cancel forwarding calls to the alternative wireless network when the signal quality on the primary wireless network reaches above the predetermined threshold. The method  40  can also optionally include the step  56  of powering down the alternative wireless network transceiver when the signal quality on the primary wireless network reaches above the predetermined threshold.  
      In a practical implementation using a dual mode phone that used an iDEN network as the primary network and CDMA as the alternative network, such a method can include the steps at the dual mode phone of powering up and camping on the iDEN network on a primary phone number and monitoring for a low signal strength on the iDEN network before powering up a CDMA modem or transceiver. In one implementation using internet traffic through the CDMA modem, the phone can request the iDEN network to forward calls to a phantom CDMA phone number. Once the dual mode phone detects an adequate signal on the iDEN network, the dual mode phone can cancel call forwarding and can power down CDMA modem.  
      Using the method  40  described above, the handset does not necessarily need to be continuously camped on both networks. The secondary modem (CDMA in this case) can be powered down when it is not needed. The secondary modem would only be powered up when the primary network (iDEN) can not receive calls and the primary phone number has been forwarded.  
      Note, the method described above also supports multiple billing methods as well. For example, a first carrier and a second carrier can negotiate rates and billing, and seamlessly bill the customer for one phone number and all his calls even though two protocols are used to deliver service. Alternately, in a different embodiment, the phone subscriber can open two separate accounts, and use CDMA and GSM for example to get a larger coverage area without either carrier knowing that there is another protocol in use for some calls.  
      In light of the foregoing description, it should be recognized that embodiments in accordance with the present invention can be realized in hardware, software, or a combination of hardware and software. A network or system according to the present invention can be realized in a centralized fashion in one computer system or processor, or in a distributed fashion where different elements are spread across several interconnected computer systems or processors (such as a microprocessor and a DSP). Any kind of computer system, or other apparatus adapted for carrying out the functions described herein, is suited. A typical combination of hardware and software could be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the functions described herein.  
      In light of the foregoing description, it should also be recognized that embodiments in accordance with the present invention can be realized in numerous configurations contemplated to be within the scope and spirit of the claims. Additionally, the description above is intended by way of example only and is not intended to limit the present invention in any way, except as set forth in the following claims.