Abstract:
A mobile terminal issues a signaling command such as a call divert message via the signaling link, along with a knowingly invalid number. The call divert request ends up being rejected by the caller&#39;s home operator due to the invalid number accompanying the call divert request. A communication server associated with the caller&#39;s mobile terminal receives the rejected request and knows how to interpret the invalid number as a service request. For example, the call divert request is to a number with a country prefix of 99 followed by a valid phone number. The communication server then interprets the request as a callback request to the valid phone number, wherein the number following the initial 99 is the destination number to call and connect with the mobile terminal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation-in-part application of U.S. patent application Ser. No. 11/487,368, filed Jun. 17, 2006, and which is incorporated herein by reference in its entirety. 
     
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a system and method for delivering services to a mobile terminal, and in particular to delivering mobile services to a roaming terminal by issuing signaling requests. 
       BACKGROUND OF THE INVENTION 
       [0003]    Mobile phone charges can be quite steep when a subscriber is located outside the influence zone of the mobile phone operator&#39;s network to which he subscribes to. When a user travels, for example, to a different country, he may be able to use his mobile phone to originate and receive calls only if his original mobile phone operator has special agreements, known in the art as “roaming agreements”, to let its own users use a different network for initial connection. 
         [0004]    For example, mobile phone user A subscribes to a mobile network Operator B. While A is traveling outside the territory where mobile Operator B is operating its mobile network, user A might be able to connect to mobile Operator C operating in said area, only if Operator B has commercial roaming agreements with Operator C. In this case, A would be allowed to use the C network to place and receive calls. 
         [0005]    It happens, in many cases, that roaming charges for receiving and placing calls on a mobile phone while temporarily connected to a different network than the one the user has subscribed to, can be very high. Even in cases where a user does not pay for receiving calls on his mobile phone while in his home network—a commercial option known as calling party pays (CPP)—the user will usually be charged for receiving calls when roaming, since mobile Operator C has to be paid in addition to mobile Operator B. 
         [0006]    When roaming, the difference between charges of incoming and outgoing calls can be very significant, sometimes at a ratio of 1:7 or even more. This situation has created opportunities for methods of communication where user A connects to user D, via a predetermined third party offering favorable commercial terms, and thus user A is not exposed to arbitrary and, in most cases, unknown roaming charges, and where some costs can be controlled and reduced significantly. 
         [0007]    Another problem roamers face frequently is that they do not enjoy the same accesses to mobile services outside their home network. While within the home network, a subscriber may be accustomed to use short-code dialing for information services such as 411 for directory assistance or 123 for accessing his voicemail. While roaming, a dialed short-code is typically first interpreted by the local operator which may not recognize the short code. In a worse scenario, the same digit combination may lead to a different service adding to the confusion and frustration of the roaming user, and incurring him unnecessary expenses. 
         [0008]    Callback is a well-known method in the industry for reducing outgoing call costs either when roaming or not. In a callback scheme, the caller typically calls a predetermined service number and is then immediate called back by the callback service. The caller needs to communicate the destination number he wishes to call and is then connected to that destination number. Since the destination number is called by the callback provider, the calling rates are known, and typically much lower than what the caller would pay in a direct dial call. One of the biggest challenges of the callback industry has been how to obtain the destination number from the caller. Some schemes ask the caller to punch in the number, which means the caller needs to either remember the number by heart or have it in front of him. A mobile user typically has many numbers in the mobile terminal memory, so they are not easily accessible during a call. Another method has the user dial the destination number while the actual call gets barred and the destination number is communicated via a Short Message (SMS). This method is easier for the caller since he dials out the destination number as if in a direct call, except that the user incurs the cost of an additional SMS message for every call attempt, even if the destination number is not available, busy or when the user mistakenly dialed a wrong number. 
         [0009]    Accordingly, there is a strong need to enable roaming mobile phone users to not only control and reduce the costs of outgoing calls but also to enable them to access mobile services in the same manner as if in the home network. Additionally, there is also a strong need to provide a callback method which is easy to use by the caller and is cost-effective. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention relates to a method for offering mobile services to a roaming mobile phone user and a system implementing said method. The present invention benefits from the fact that most telephone networks establish a voice or data call using voice or data channels and an independent signaling channel. The caller is not billed for information exchanged on the signaling channel. Billing only occurs when an actual voice or data call is established on the remaining non-signaling channels. 
         [0011]    The method of the invention consists of issuing a signaling Supplementary Service command such as a call divert message via the signaling link, along with a knowingly invalid number. The call divert request ends up being rejected by the caller&#39;s home operator due to the invalid number accompanying the call divert request. A communication server of the invention associated with the caller&#39;s mobile terminal receives the rejected request and knows how to interpret the invalid number as a service request. In one preferred embodiment of the present invention, the call divert request is to a number with a dummy country prefix of 99 followed by a valid phone number. The communication server then interprets the request as a callback request to the valid phone number, wherein the number following the initial 99 is the destination number to call and connect with the mobile terminal. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an overview of a GSM (Global System for Mobile Communications) network as known in the art. 
           [0013]      FIG. 2  is a block diagram of a roaming mobile terminal connecting to its home network, in which the home network includes a communication server used by the invention. 
           [0014]      FIG. 3  shows a service number comprised of a dummy prefix and a service request code. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    In the following detailed description of various embodiments, reference is made to the accompanying drawings that form a part thereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
         [0016]    The present invention relates to a method for offering mobile services to a roaming mobile phone user and a system implementing said method. A method is disclosed for delivering a mobile service to a mobile terminal, wherein the mobile terminal contains software or hardware logic adapted to generate a service call to a communication server, the method comprising the steps of: 
         [0000]    (i) dialing out a destination number on the mobile terminal;
 
(ii) intercepting the call by said adapted software or hardware logic on the mobile terminal and creating a service number comprising a service request code;
 
(iii) issuing a signaling request with an associated service number by the adapted software or hardware logic on the mobile terminal;
 
(iv) transferring the signaling request via a signaling channel for authorization;
 
(v) rejecting the signaling request;
 
(vi) receiving the service number associated with the signaling request by the communication server; and
 
(vii) reading the service request code from the received service number, and performing the mobile service associated with said service request code.
 
         [0017]    Most telephone networks employ a separate, dedicated signaling channel or link responsible for establishing and terminating calls. Additional links or channels are used exclusively for the transmission of voice or data. The most common signaling method today is known as Signaling System #7 (SS7). SS7 is also referred to as “Common Channel Signaling System 7” (CCSS7) in North America. In some European countries, specifically the United Kingdom, it is sometimes called C7 (CCITT number 7) and is also known as number 7 and CCIS7. SS7 provides a universal structure for telephony network signaling, messaging, interfacing, and network maintenance. It deals with establishment of a call, exchanging user information, call routing, different billing structures, and supports Intelligent Network (IN) services. Integrated Services Digital Network (ISDN) is another common channel signaling method. 
         [0018]    The term “mobile terminal” as referred to herein means any mobile device with telephony capabilities or that can be augmented with telephony capabilities. Examples include, but are not limited to: mobile phones, Personal Digital Assistants (PDA&#39;s), portable computers, portable media playing devices, portable game consoles and others. 
         [0019]      FIG. 1  is an overview of a generic GSM network of the art and its major components. The diagram and description below are available on the following Internet site: http://www.shoshin.uwaterloo.ca/˜jscouria/GSM/gsmreport.html. A GSM network is composed of several functional entities, whose functions and interfaces are specified. The GSM network can be divided into three broad parts. The Mobile Station is carried by the subscriber. The Base Station Subsystem controls the radio link with the Mobile Station. The Network Subsystem, the main part of which is the Mobile services Switching Center (MSC), performs the switching of calls between the mobile users, and between mobile and fixed network users. The MSC also handles the mobility management operations. Not shown is the Operations and Maintenance Center, which oversees the proper operation and setup of the network. The Mobile Station and the Base Station Subsystem communicate across the Um interface, also known as the air interface or radio link. The Base Station Subsystem communicates with the Mobile services Switching Center across the A interface. 
         [0020]    The mobile station (MS) consists of the mobile equipment (the terminal) and a smart card called the Subscriber Identity Module (SIM). The SIM provides personal mobility, so that the user can have access to subscribed services irrespective of a specific terminal. By inserting the SIM card into another GSM terminal, the user is able to receive calls at that terminal, make calls from that terminal, and receive other subscribed services. 
         [0021]    The mobile equipment is uniquely identified by the International Mobile Equipment Identity (IMEI). The SIM card contains the International Mobile Subscriber Identity (IMSI) used to identify the subscriber to the system, a secret key for authentication, and other information. The IMEI and the IMSI are independent, thereby allowing personal mobility. The SIM card may be protected against unauthorized use by a password or personal identity number. 
         [0022]    The Base Station Subsystem is composed of two parts, the Base Transceiver Station (BTS) and the Base Station Controller (BSC). These communicate across the standardized Abis interface, allowing (as in the rest of the system) operation between components made by different suppliers. 
         [0023]    The Base Transceiver Station houses the radio transceivers that define a cell and handles the radio-link protocols with the Mobile Station. In a large urban area, there will potentially be a large number of BTSs deployed, thus the requirements for a BTS are ruggedness, reliability, portability, and minimum cost. 
         [0024]    The Base Station Controller manages the radio resources for one or more BTSs. It handles radio-channel setup, frequency hopping, and handovers. The BSC is the connection between the mobile station and the Mobile service Switching Center (MSC). 
         [0025]    The central component of the Network Subsystem is the Mobile services Switching Center (MSC). It acts like a normal switching node of the Public Switched Telephone Network (PSTN) or ISDN, and additionally provides all the functionality needed to handle a mobile subscriber, such as registration, authentication, location updating, handovers, and call routing to a roaming subscriber. These services are provided in conjunction with several functional entities, which together form the Network Subsystem. The MSC provides the connection to the fixed networks (such as the PSTN or ISDN). Signaling between functional entities in the Network Subsystem uses Signaling System Number 7 (SS7), used for trunk signaling in ISDN and widely used in current public networks. 
         [0026]    The Home Location Register (HLR) and Visitor Location Register (VLR), together with the MSC, provide the call-routing and roaming capabilities of GSM. The HLR contains all the administrative information of each subscriber registered in the corresponding GSM network, along with the current location of the mobile. The location of the mobile is typically in the form of the signaling address of the VLR associated with the mobile station. There is logically one HLR per GSM network, although it may be implemented as a distributed database. 
         [0027]    The Visitor Location Register (VLR) contains selected administrative information from the HLR, necessary for call control and provision of the subscribed services, for each mobile currently located in the geographical area controlled by the VLR. Although each functional entity can be implemented as an independent unit, all manufacturers of switching equipment to date implement the VLR together with the MSC, so that the geographical area controlled by the MSC corresponds to that controlled by the VLR, thus simplifying the signaling required. Note that the MSC contains no information about particular mobile stations—this information is stored in the location registers. 
         [0028]    The other two registers are used for authentication and security purposes. The Equipment Identity Register (EIR) is a database that contains a list of all valid mobile equipment on the network, where each mobile station is identified by its International Mobile Equipment Identity (IMEI). An IMEI is marked as invalid if it has been reported stolen or is not type approved. The Authentication Center (AuC) is a protected database that stores a copy of the secret key stored in each subscriber&#39;s SIM card, which is used for authentication and encryption over the radio channel. 
         [0029]    Supplementary services (SS) in GSM are a means of enriching the user experience. An SS may, for example, forward a call in the case of no reply from the called party, bar certain outgoing or incoming calls, show the number of the calling party to the called party, etc. In order to use an SS, a GSM user needs a subscription to that SS. The subscription to supplementary services is contained in the HLR and is sent to the MSC/VLR during registration. The supplementary services are fully standardized, as listed in Table 1 below. A GSM subscriber can therefore use his supplementary services in any GSM network, provided that the network supports these supplementary services, and thus enjoy the same user experience. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 GSM Supplementary Services 
               
             
          
           
               
                 SS group 
                 Supplementary services 
                 GSM TS 
               
               
                   
               
               
                 Line identification 
                 Calling line identification presentation (CLIP) 
                 02.81 [13] 
               
               
                   
                 Calling line identification restriction (CLIR) 
               
               
                   
                 Connected line presentation (COLP) 
               
               
                   
                 Connected line restriction (COLR) 
               
               
                 Name identification 
                 Calling name presentation (CNAP) 
                 02.96 [24] 
               
               
                 Call forwarding 
                 Call forwarding - unconditional (CFU) 
                 02.82 [14] 
               
               
                   
                 Call forwarding - busy (CFB) 
               
               
                   
                 Call forwarding - no reply (CFNRY) 
               
               
                   
                 Call forwarding - not reachable (CFNRC) 
               
               
                   
                 Call deflection (CD) 
                 02.72 [11] 
               
               
                 Call offering 
                 Explicit call transfer (ECT) 
                 02.91 [22] 
               
               
                 Call completion 
                 Call waiting (CW) 
                 02.83 [15] 
               
               
                   
                 Call hold (CH) 
               
               
                   
                 Call completion to busy subscriber (CCBS) 
                 02.93 [23] 
               
               
                   
                 Multi-call (MC) 
                 22.135 [69] a    
               
               
                 Multi-party 
                 Multi-party call (MPTY) 
                 02.84 [16] 
               
               
                 Community of interest 
                 Closed user group (CUG) 
                 02.85 [17] 
               
               
                 Charging 
                 Advice of charge - information (AOCI) 
                 02.86 [18] 
               
               
                   
                 Advice of charge - charge (AOCC) 
               
               
                 Additional information transfer 
                 User-to-user signalling - service 1 (UUS1) 
                 02.87 [19] 
               
               
                   
                 User-to-user signalling - service 2 (UUS2) 
               
               
                   
                 User-to-user signalling - service 3 (UUS3) 
               
               
                 Call baring 
                 Barring of all outgoing calls (BAOC) 
                 02.88 [20] 
               
               
                   
                 Barring of outgoing international calls (BOIC) 
               
               
                   
                 Barring of outgoing international calls except to the 
               
               
                   
                 home country (BOIC-exHc) 
               
               
                   
                 Barring of all incoming calls (BAIC) 
               
               
                   
                 Barring of all incoming calls when roaming 
               
               
                   
                 (BICROAM) 
               
               
                 Call priority 
                 enhanced multi-level precedence and pre-emption 
                 02.67 [10] 
               
               
                   
                 (eMLPP) 
               
               
                   
               
               
                   a For the multi-call service, there is no GSM TS available, but only a 3GPP TS (22.135). 
               
             
          
         
       
     
         [0030]    In another aspect of the present invention, the invention relates to a telephony system for delivering a mobile service to a mobile terminal, wherein the mobile terminal contains software or hardware logic adapted to generate a service call to a communication server, said system comprising: 
         [0000]    (i) a mobile terminal adapted to dial out a destination number;
 
(ii) adapted software or hardware logic on the mobile terminal configured to intercept said destination number and create a service number comprising a service request code;
 
(iii) means for issuing a signaling request with an associated service number;
 
(iv) means for transferring the signaling request via a signaling channel for authorization;
 
(v) means for rejecting said the signaling request; and
 
(vi) a communication server adapted to receive the service number associated with the signaling request, read the service request code from the received service number, and perform the mobile service associated with said service request code.
 
         [0031]      FIG. 2  is a block diagram of a roaming mobile terminal  10  connecting to its home network. When roaming, the mobile terminal  10  is connected to a different operator or service provider than its home provider. The home provider is defined as the service provider with which the user has a direct billing relationship and who authorizes the calls made by the mobile terminal  10 . When attempting to establish a call, the mobile terminal  10  connects to the roaming network local switch, marked in  FIG. 2  as roaming switch  20 . When the mobile terminal  10  attempts to make a call, the roaming switch  20  contacts the home switch  25  for authorization. Information regarding the identity of the mobile terminal  10  and the nature of the request are passed from the Visitor Location Register (VLR)  30  of the roaming or visiting network to the home networks&#39; Home Location Register (HLR)  35 . The two networks, the roaming network and the home network are connected via voice channels  40  and a signaling link  45 . A communication server  50  of the invention is associated with the HLR  35  for exchanging information. 
         [0032]    In one preferred embodiment of the present invention, the service request code is based on the destination number, for example, in order to perform a callback service connecting the mobile terminal  10  to the destination number. 
         [0033]    In another preferred embodiment of the present invention, the service number comprises a dummy prefix and a service request code. In yet another preferred embodiment of the present invention, the service number consists of a dummy prefix and a service request code. 
         [0034]      FIG. 3  shows a service number  60  comprised of a dummy prefix  65  and a service request code  67 . In one preferred embodiment of the present invention, the number 99 is used as the dummy prefix  65 . The number 99 is a good choice for a dummy prefix  65  since it does not correspond to any country prefix. The service request code  67  example shown in  FIG. 3  is a telephone number in France (country code  33 ). 
         [0035]    The services provided by the invention to the mobile terminal  10  are based on the callback mechanism wherein the mobile terminal  10  gets called back within seconds and then connected to the desired phone number. The process starts when the user of the mobile terminal  10  dials a destination telephone number. Adapted software or hardware logic on the mobile terminal  10  intercepts the call, stores the destination number in a temporary storage location, and creates a service number  60 . The service number  60  is composed of two parts: a dummy prefix  65  and a service request code  67 . The dummy prefix  65  is usually a predetermined number, for example, 99. The service request code  67  is based on the destination number dialed by the mobile terminal  10  and may also be identical to the destination number. 
         [0036]    The adapted software or hardware logic on the mobile terminal  10  then proceeds to issue a signaling request with an associated service number  60 . In one preferred embodiment of the present invention the signaling request is a Supplementary service request. In another preferred embodiment of the present invention the signaling request is a call divert request. A call divert request, sometimes also termed call forward request, is a request to transfer all incoming calls to a different phone number. For example, when traveling some people may wish to transfer all calls received to their home or office to their mobile phone. The signaling request along with the associated service number  60  are then transmitted via the signaling link  45  for authorization. The signaling request arrives to the HLR  35  for authorization. The signaling request will always end up being refused due to the dummy prefix  65  that is not a valid beginning of a valid phone number. In one preferred embodiment of the present invention, the communication server  50  receives the signaling request and service number  60  from the HLR  35 , and instructs the HLR to reject the signaling request. In another preferred embodiment of the present invention, the communication server  50  instructs the HLR  35  to always reject signaling requests with service numbers  60  that start with a dummy prefix  65 . After rejecting the signaling request, the HLR  35  forwards the communication server  50  the rejected signaling request and service number  60 . 
         [0037]    Once the communication server  50  receives rejected signaling request and service number  60  it looks at the service request code  67  and performs the service associated with that service request code  67 . Examples of mobile services the communication server  50  can perform comprise: callback, voicemail, short-code dialing, information services, billing services, prepaid services, data services or directory assistance. 
         [0038]    In a callback service, the communication server  50  receives the destination number in the service request code  67 . The communication server  50  then dials back the telephone number associated with the mobile terminal  10 , followed by dialing the destination number, and then connects the mobile terminal  10  with the destination number. 
         [0039]    If the service request code  67  is for voicemail, the communication server  50  then dials user&#39;s voicemail number, dials back the mobile terminal  10  and then connects the two. 
         [0040]    If the service request code  67  is for billing services either prepaid or postpaid, the communication server  50  can then receive information about the caller&#39;s billing status, available credit, newly added credit etc. 
         [0041]    If the service request code  67  is identified as a short-code, the communication server  50  retrieves the telephone number associated with the dialed short-code and then dials the retrieved phone number, dials back the mobile terminal  10  and then connects the two. Depending on the mobile service requested by the user, the communication server  50  either retrieves a number from the roaming network or from the home network. If the user, for example, dials a short-code number for a taxi service, the communication server  50  will look up a taxi service in the area the user is roaming. If on the other hand, the user dials a short-code for a sports scores service, the communication server  50  will look up the sports news service in the user&#39;s home network. 
         [0042]    Although the invention has been described in detail, nevertheless changes and modifications, which do not depart from the teachings of the present invention, will be evident to those skilled in the art. Such changes and modifications are deemed to come within the purview of the present invention and the appended claims.