Abstract:
Reliable call hand-offs from a cellular network to a Wi-Fi network. A hand-off controller detects a hand-off condition (e.g., hand-off request, potential/predicted hand-off request) and, in response, initiates a test call. For example, a telephone call made through a smart phone, using a cellular network (e.g., Verizon, AT&amp;T or Sprint) can be handed over to a hot spot at a Starbucks. In response to detecting an available data network, transmission quality for VOIP conditions is automatically tested. If the network conditions meet a certain predetermined threshold, the VOIP hand-off is executed. If the predetermined threshold is not met, the VOIP hand-off may not be executed, or may be delayed.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to Wi-Fi computer networking, and more specifically, to transferring calls between a cellular network to a Wi-Fi network at a specified quality. 
       BACKGROUND 
       [0002]    The advancement of VOIP technology allows mobile devices to move bandwidth from voice networks, such as GSM/CDMA/LTE to Wi-Fi portions of data communication networks. Traditionally, voice calls were conducted completely over voice networks. However, VOIP calls, bolstered in part by faster, more reliable, networks, are being utilized more and more to handle voice calls. Free hot spots and unlimited data plans make data voice calls an attractive alternative to the tolled cellular networks. 
         [0003]    Currently available applications for switching to a data network require manual intervention. Once an access point of a sufficient RSSI is identified, a hand-over can be initiated. Problematically, the reliability of some data networks can be low, due to network congestion, time of day, and various other factors. Network reliability can change over time as network conditions change. Accordingly, it may not always be desirable to change networks during a single voice call. 
         [0004]    What is needed is a robust technique for more reliable call hand-offs from cellular networks to Wi-Fi networks. The technique can use a test VOIP call, for quality control, prior to the hand-off from a cellular network to a data network. 
       SUMMARY 
       [0005]    The above-mentioned shortcomings are addressed by the present disclosure of a hand-off control system for handing-off calls from a cellular network to a data network. 
         [0006]    In one embodiment, a hand-off controller detects a hand-off condition (e.g., hand-off request, potential/predicted hand-off request) and, in response, initiates a test call. For example, a telephone call made through a smart phone, using a cellular network (e.g., Verizon, AT&amp;T or Sprint) can be handed over to a hot spot at a Starbucks. In response to detecting an available data network, transmission quality for VOIP conditions is automatically tested. Network conditions are measured during a test VOIP call (e.g., latency, error rate, network congestion, packet collisions, processor load, queue capacity, storage capacity, and periodic goals). If the network conditions meet a certain predetermined threshold, the VOIP hand-off is executed. 
         [0007]    If the predetermined threshold is not met, the VOIP hand-off may not be executed, or may be delayed. In an embodiment, a new server or service is tested responsive to a previous server or service failing to meet the predetermined threshold. 
         [0008]    Advantageously, reliability is increased when handing-off from a cellular network to a data network. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    In the following drawings, like reference numbers are used to refer to like elements. Although the following figures depict various examples of the invention, the invention is not limited to the examples depicted in the figures. 
           [0010]      FIG. 1A  is a block diagram illustrating a hand-off control system, based in a station making a call, for handing-off calls from a cellular network to a data network, according to an embodiment. 
           [0011]      FIG. 1B  is a block diagram illustrating a hand-off control system, based in a network, for handing-off calls from a cellular network to a data network, according to an embodiment. 
           [0012]      FIG. 2  is a more detailed block diagram illustrating a hand-off controller of  FIG. 1 , according to an embodiment. 
           [0013]      FIG. 3  is a flow chart illustrating a method for reliable VOIP hand-offs from cellular networks to Wi-Fi networks, according to an embodiment. 
           [0014]      FIG. 4  is a more detailed flow chart illustrating a step for using conditions from a test call prior to hand-offs from cellular networks to Wi-Fi networks of  FIG. 3 , according to an embodiment. 
           [0015]      FIG. 5  is a block diagram illustrating an exemplary computing device, according to one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Hand-off control systems, computer-implemented methods, and (non-transitory) computer-readable mediums for handing-off calls from a cellular network to a data network, are described. Hand-offs are generally referred to herein as moving from cellular networks to data networks, however, hand-off can also occur in the opposite direction. 
         [0017]    Systems for Reliable Network Hand-Offs ( FIG. 1-2 ) 
         [0018]      FIG. 1A  is a block diagram illustrating a hand-off control system  100  for handing-off calls from a cellular network  101  to a data network  102 , according to an embodiment. The system  100  comprises a network hand-off controller  105  and a station  110 , communicatively coupled through the backbone infrastructure. A call controller  121  and a cell tower  131  are communicatively coupled to the cellular network  101 . A Wi-Fi controller  122  and an access points  132  are communicatively coupled to the Wi-Fi data network  102 . The station  110  is within radio range of both the cell tower  131  and the access point  132 . Additional network components can also be part of the system  100 , such as firewalls, virus scanners, routers, switches, application servers, databases, as well as additional controllers, access points, access switches, stations, and the like. For instance, embodiments of the system  100  can be implemented in conjunction with a network security system, for example, the FortiGate Network Security platform by Fortinet of Sunnyvale, Calif. The network components can be implemented as hardware, software, or a combination of both. 
         [0019]    Wireless components preferably use communication protocols such as IEEE 802.11 n and IEEE 802.11 ac wave 2, in addition to other protocols such as other IEEE 802.11s, IEEE 802.3, Bluetooth, 3G and 4G. The enterprise network can serve, for example, a business enterprise, a hospital or system of hospital, school, building, a private network, or the like. The enterprise network  101  can provide access to a wide area network or the Internet in some embodiments. Alternatively, the enterprise network  101  can be distributed over the Internet, in other embodiments. A combination of wired and wireless devices can be connected, as well as only wireless devices or only wired devices. The enterprise network can be, for example, the Internet, a cellular network, a larger enterprise network to which the enterprise network is a smaller component of, or a combination of network types. 
         [0020]    A network hand-off controller  105 A can be implemented in the station  110 . The network hand-off controller  105 A starts off in communication with the cellular network  101  when a hand-off condition is detected. Additionally, the network hand-off controller  105 A is in communication with the Wi-Fi data network  102  to test a VOIP call, and if the quality is high enough, permit a hand-off to occur. The hand-off condition can be, without limitation, an actual request for a hand-off originating with the station  110 , a predicted hand-off based, for example, on a rate of movement for the station  110 , a forced hand-of initiated by a network device, low quality of service, or a network policy. A policy can initiate a hand-off from a fee-based cellular network whenever a free Wi-Fi connection is available. Still another policy automatically hands-off when indoors, or when cellular quality drops. In another embodiment, an RSSI signal determines when a hand-off is possible and can be a network condition triggering the hand-off voice call. 
         [0021]    However, additional analysis is first completed before the network hand-off controller  105 A permits the hand-off. More specifically, hand-off conditions can include one or more of: quality of service, network policies, latency, error rate, network congestion, packet collisions, processor load, queue capacity, and storage capacity. In one case, an explicit hand-off request is intercepted and delayed until testing is complete. This additional analysis can be in addition to standard protocol actions for hand-offs. 
         [0022]    The network hand-off controller  105 A is a general representation of one or more devices and/or processes, implementing the hand-off. In one implementation, the network hand-off controller  105  is a single, centralized apparatus. In another implementation, a distributed architecture leverages clients on one or more of the station  110 , the call controller  121 , cell tower  131 , the Wi-Fi controller  122 , and the access point  132 . One example of a network hand-off controller  105  is a GSM/Wi-Fi gateway. Detailed embodiments of components within the hand-off controller  105  are set forth below with respect to  FIG. 3 . 
         [0023]    The station  110  places and receives voice calls using various types of networks. During a voice call, a user in motion can cause a hand-off of the station  110  between two different networks as one becomes more suitable for the new location. In an embodiment, the station  110  includes a cellular radio and a Wi-Fi radio on board. The station  110  can sense the Settings for hand-offs can be configured through a user interface of the station  110 . The station  110  can be, for example, a personal computer, a laptop computer, a tablet computer, a smart phone, a mobile computing device, a server, a cloud-based device, a virtual device, an Internet appliance, or any of the computing devices described herein (see e.g.,  FIG. 5 ). No special client is needed for this particular technique, although other aspects of the network may require downloads to the station  110 . The station  110  access, for example, a LAN (local area network) or external networks using an RF (radio frequency) antenna and network software complying with IEEE 802.11. 
         [0024]    The access point  132  provides a connection for the station  110  to the Wi-Fi data network  102  to continue a voice call that has been handed-off. A BSSID is advertised to the station  110  through beacon frames, to facilitate an authorized connection from the station  110  to the access point  132 . The access point  132  can also have additional processes for handling handed-off calls or VOIP calls. 
         [0025]    Physically, the access point  132  include one or more individual access points implemented in any of the computing devices discussed herein (e.g., see  FIG. 5 ). For example, the access point  132  can be an AP  110  or AP  433  (modified as discussed herein) by Meru Networks of Sunnyvale, Calif. A network administrator can strategically place the access point  132  for optimal coverage area over a locale. The access point  132  can, in turn, be connected to a wired hub, switch or router connected to the enterprise network (or an external network). In embodiment, access point functionality is incorporated into a switch or router. In another embodiment, the access point  132  is a virtual device. 
         [0026]    The Wi-Fi controller  122  manages a group of access points on the Wi-Fi data network  102 , including the access point  132 . Internal hand-offs between access points within the Wi-Fi data network  102  can be initiated, assisted, or facilitated by the Wi-Fi controller  122 . 
         [0027]    The Wi-Fi controller  122  can be implemented in any of the computing devices discussed herein (e.g., see  FIG. 3 ). For example, the cloud-based Wi-Fi controller  122  can be an MC1500 or MC6000 device (e.g., modified) by Meru Networks of Sunnyvale, Calif. Additional functionalities of the Wi-Fi controller  110  include management of the access point  120 . Further, virtual cell and virtual port services leverage the network-wide view of the system  100  available to the Wi-Fi controller  122 . 
         [0028]    The cellular call controller  121 , in an embodiment, has a first module to control intra-network hand-offs of a call, for example, between cell towers. The cell tower  131  can have local processing and antennae modules for exchanging signals with the station  110  while within range. 
         [0029]    In contrast to  FIG. 1A  in which the network hand-off controller  105 A is implemented in the station  110 , the network hand-off controller  105 B of  FIG. 1B  is implemented as a network-based device. Similar components perform similar processes to generate the common result of making a test call prior to switching networks. In some embodiments, the station  110  (and other components) can have mobile apps for optimizing operations. 
         [0030]      FIG. 2  is a more detailed block diagram of the network hand-off call controller  105  (representative of either  105 A or  105 B), according to an embodiment. The network hand-off controller  105 A comprises a hand-off detection module  210 , a test call quality module  220 , and a radio controller  230 . Many other configurations are possible. 
         [0031]    The hand-off detection module  210  determines that a hand-off is being attempted or will be attempted. In the case of an attempt, a command to hand-off can be intercepted and temporarily delayed until allowed to go forward. In the case of a predicted attempt, the test call can be conducted before an actual attempt is made. 
         [0032]    The test call quality module  220 , in one embodiment, makes a new VOIP call using a new network, while the station  110  is still processes the existing call on the existing network. The test call operates in the background and can be without knowledge to a user of the station  110  and without the access point  132  knowing that the call is just a test versus an actual call. A standard telephone number can be used to facilitate the test call completely from the station  110 . In other embodiments, the access point  132  can have local processes that assist the test call. For example, a certain telephone number can be used for test calls which the access point  132  recognizes. In some embodiments, a separate processor or a separate thread on a multi-threaded processor or a multi-threaded operating system can isolate computing resources for the concurrent calls, in some embodiments, to prevent loss of quality on the existing call. 
         [0033]    The radio controller  230  executes hand-offs that are allowed to go forward by moving a voice data stream originating at higher layers from a cellular radio to a Wi-Fi radio. There can be some duplicity during the transfer over both radios until it is confirmed that the VOIP call is prepared. For example, a higher-layer voice application executing on the station  110  can send a digitized stream of voice data to the lower layers for sending through a communication channel. The radio controller  230  can set a bit to 0 or 1 indicating which communication channel to use. Following the cellular communication channel, a 3G or 4G radio can be accessed, while following the data communication channel, a Wi-Fi radio can be accessed. Before being transmitted over an RF antenna from the Wi-Fi radio, additional processes can take place, such as encoding, error checking, and the like. 
         [0034]    Methods for Reliable Network Hand-Offs ( FIG. 3-4 ) 
         [0035]      FIG. 3  is a flow chart illustrating a method  300  for reliable VOIP hand-offs from cellular networks to Wi-Fi networks, according to an embodiment. The process at a high-level is implementable by computer hardware, wherein individual components can perform individual steps of a method. 
         [0036]    In method  300 , a user is engaged in a call using a telephone device over a cellular network (step  310 ). Using conditions from a test call prior to handing-off the call from the cellular network to a data network (step  320 ), an example of which is set forth below with respect to  FIG. 3 . The user continues engaging in the call using the telephone device over a data network (step  330 ). 
         [0037]    One of ordinary skill in the art will recognize that the method  300  (and others) is non-limiting as other embodiments can have more or less steps and can be performed in a different order. The method  300  can be implemented in the system  100  of  FIG. 1  or in other components. 
         [0038]      FIG. 4  is a flow chart illustrating the step  320  of using conditions from a test call prior to hand-offs from cellular networks to Wi-Fi networks, according to an embodiment. 
         [0039]    Responsive to detecting a hand-off condition (step  410 ), a test call is initiated over a data network to determine network conditions (step  420 ). Test call data is compare dot pre-determined threshold conditions (step  430 ). If real-time network conditions meet pre-determined threshold conditions, a hand-off is allowed (step  450 ). If real-time network conditions to not meet pre-determined conditions, a hand-off may be precluded (sate  460 ). In some cases, other conditions are also taken into account. 
         [0040]    Generic Computing Device ( FIG. 5 ) 
         [0041]      FIG. 5  is a block diagram illustrating an exemplary computing device  500  for use in the system  100  of  FIG. 1 , according to one embodiment. The computing device  500  is an exemplary device that is implementable for each of the components of the system  100 , including the network hand-off controller  105 , the access points  132 , and the station  110 . The computing device  500  can be a mobile computing device, a laptop device, a smartphone, a tablet device, a phablet device, a video game console, a personal computing device, a stationary computing device, a server blade, an Internet appliance, a virtual computing device, a distributed computing device, a cloud-based computing device, or any appropriate processor-driven device. 
         [0042]    The computing device  500 , of the present embodiment, includes a memory  510 , a processor  520 , a storage drive  530 , and an I/O port  540 . Each of the components is coupled for electronic communication via a bus  599 . Communication can be digital and/or analog, and use any suitable protocol. 
         [0043]    The memory  510  further comprises network applications  512  and an operating system  514 . The network applications  512  can include the modules of the network hand-off controller  105 , the call controller  121 , the Wi-Fi controller  122 , the cell tower  151  and the access point  152 . Other network applications  512  can include a web browser, a mobile application, an application that uses networking, a remote application executing locally, a network protocol application, a network management application, a network routing application, or the like. 
         [0044]    The operating system  514  can be one of the Microsoft Windows® family of operating systems (e.g., Windows 95, 98, Me, Windows NT, Windows 2000, Windows XP, Windows XP x64 Edition, Windows Vista, Windows CE, Windows Mobile, Windows 5 or Windows 8), Linux, HP-UX, UNIX, Sun OS, Solaris, Mac OS X, Alpha OS, AIX, IRIX52, or IRIX64. Other operating systems may be used. Microsoft Windows is a trademark of Microsoft Corporation. 
         [0045]    The processor  520  can be a network processor (e.g., optimized for IEEE 802.11), a general purpose processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a reduced instruction set controller (RISC) processor, an integrated circuit, or the like. Qualcomm Atheros, Broadcom Corporation, and Marvell Semiconductors manufacture processors that are optimized for IEEE 802.11 devices. The processor  520  can be single core, multiple core, or include more than one processing elements. The processor  520  can be disposed on silicon or any other suitable material. The processor  520  can receive and execute instructions and data stored in the memory  510  or the storage drive  550   
         [0046]    The storage drive  530  can be any non-volatile type of storage such as a magnetic disc, EEPROM, Flash, or the like. The storage drive  550  stores code and data for applications. 
         [0047]    The I/O port  540  further comprises a user interface  542  and a network interface  544 . The user interface  542  can output to a display device and receive input from, for example, a keyboard. The network interface  544  (e.g. RF antennae) connects to a medium such as Ethernet or Wi-Fi for data input and output. 
         [0048]    Many of the functionalities described herein can be implemented with computer software, computer hardware, or a combination. 
         [0049]    Computer software products (e.g., non-transitory computer products storing source code) may be written in any of various suitable programming languages, such as C, C++, C#, Oracle® Java, JavaScript, PHP, Python, Perl, Ruby, AJAX, and Adobe® Flash®. The computer software product may be an independent application with data input and data display modules. Alternatively, the computer software products may be classes that are instantiated as distributed objects. The computer software products may also be component software such as Java Beans (from Sun Microsystems) or Enterprise Java Beans (EJB from Sun Microsystems). 
         [0050]    Furthermore, the computer that is running the previously mentioned computer software may be connected to a network and may interface to other computers using this network. The network may be on an intranet or the Internet, among others. The network may be a wired network (e.g., using copper), telephone network, packet network, an optical network (e.g., using optical fiber), or a wireless network, or any combination of these. For example, data and other information may be passed between the computer and components (or steps) of a system of the invention using a wireless network using a protocol such as Wi-Fi (IEEE standards 802.11, 802.11a, 802.11b, 802.11e, 802.11g, 802.11i, 802.11n, and 802.11ac, just to name a few examples). For example, signals from a computer may be transferred, at least in part, wirelessly to components or other computers. 
         [0051]    In an embodiment, with a Web browser executing on a computer workstation system, a user accesses a system on the World Wide Web (WWW) through a network such as the Internet. The Web browser is used to download web pages or other content in various formats including HTML, XML, text, PDF, and postscript, and may be used to upload information to other parts of the system. The Web browser may use uniform resource identifiers (URLs) to identify resources on the Web and hypertext transfer protocol (HTTP) in transferring files on the Web. 
         [0052]    This description of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to a particular use. The scope of the invention is defined by the following claims.