GB2369971A - Reverse charge connection for mobile using USSD - Google Patents

Abstract

A reverse charge call identifier in a Unstructured Supplementary Service Data (USSD) signal is received by a controller, which connects to the requested telephone number. Information extracted from the USSD signal, relating to the calling mobile telephone number is passed to the requested number. Both the calls from mobile to controller and controller to acceptor of the reverse charge call, may be charged to the acceptor.

Description

Telecommunications Services Apparatus

This invention relates to a telecommunications services apparatus for use with a mobile radio telecommunications system, such as a mobile telephone system.

Pre-pay mobile telephony has opened up access to mobile phones to a large number of people who were previously not mobile phone users. It provides benefits to both the user and the network operator. For the user it offers freedom from a bill, and allows ongoing cost control. It also offers anonymity in some cases. For the network operator it improves cash flow and, since all payments are in advance, offers protection from bad debt.

However there are some difficulties with providing a full range of services to pre-pay customers. One of the problems is that users can effectively be anonymous, by purchasing a phone package and airtime credit over the counter with no requirement for their identity to be known by the network. Consequently, all actions by the user which incur a cost (e. g. making a call, or sending a message) require the network to interact with a credit store or database before permitting the action to take place.

Failure to do this could lead to users defrauding the network by obtaining services for which they had insufficient credit. This problem does not arise for tariffed (or'postpaid') subscribers, whose identity is known to the network by registration and who can be billed after the event.

The pre-pay credit management has been done in several different ways, including databases with credit stored in the network, and schemes with credit stored in the phone's SIM (Subscriber Identity Module) card. Of these the SIM card scheme is regarded as less secure. All of these schemes require communication with the user's home network, for example to provide authorisation to use a service or to clear a call once credit runs out.

Although this is easily achieved for calls made in the home network, it is more difficult to achieve in a consistent way when the user is roaming on another network.

Charging difficulties apply to both incoming and outgoing calls for roaming pre-pay users, because in both cases the user pays for the call leg between the home network and the roaming mobile.

For this reason, most pre-pay schemes did not initially support roaming users, and solutions which support roaming are only now beginning to be rolled out successfully.

Pre-pay packages normally include an initial credit allowance. Users can obtain more airtime credit in a number of ways, depending upon the network operator's commercial offering. In most cases users buy airtime vouchers from a variety of retail outlets and make a (normally free) call to register the credit. In some cases users will purchase airtime using a credit card over the air, i. e. during a (normally free) call to the pre-pay system.

Of course, in certain circumstances, a user may run out of credit and may not have or be able to easily obtain a top-up voucher. This may often occur with young people, who typically have pre-pay phones, and may prevent from them calling home - an unsatisfactory situation.

Further difficulties may arise for pre-pay users when roaming in a foreign country. For a start, they may not be able to purchase additional airtime locally. Even if they have vouchers or the facility to use a credit card to buy airtime, the (normally free) top-up call that they would make in the home network may not be possible in a roaming network. This could be either because the short dialling code is not available in the roaming network, or because they do not have sufficient credit to make the topup call.

A means of overcoming these problems, which would allow mobile phone users to make calls when they have no credit or when the normal method of call origination is disallowed for some reason, would be highly desirable.

Such a facility could be provided if it were possible to reverse the call charges, i. e. the call could be billed to the called party, rather than to the calling party.

Availability of a reverse charge service for mobile users could bring other benefits and uses. For example, parents may provide children with pre-pay phones and a certain amount of airtime for general use, but to reduce the likelihood of there being no credit in an"emergency"they may be prepared to pay for calls from their children to the home fixed-line number or to their own mobile phones on those respective accounts.

In addition, companies may be prepared to pay for calls from staff who use their own mobile phones (pre-pay or post-pay) to call the office. In this case, a simple method of reversing the charges would be highly desirable, as opposed to the employee paying for the call (either in advance with pre-pay, or later under a contract) and then re-claiming the amount as expenses. The administrative costs of handling such expense claims may often be more than the cost of the call.

Reverse charge (or collect) calls, by which the charge for a telephone call can be billed to the recipient of the call rather than the initiator, have been known for many years.

Normally such calls have been made by request to an operator, who would ask for the required telephone number, place a call to that number, announce that there is a reverse charge call from the particular area or country and, if the call is accepted, make the connection between caller and destination. In recent years, some network operators have implemented Automated Reverse Charge services in which an Interactive Voice Response (IVR) system performs the dialogue with both the calling and called parties, making the connection if appropriate.

These services have been available for callers on the fixed network and are normally accessed by dialling a telephone number which is not billed to the caller, e. g. a short code or an 0800 (freephone) number in the UK.

Travellers outside their home country have typically been able to make a reverse charge call by dialling the Country Direct service, for example callers in the UK can dial, free of charge, 0800 890031 for Netherlands Direct.

However, whilst mobile users can usually access 0800 numbers by dialling an alternative code such as an 800 or *0800, they are normally charged for the call at standard rates (because of the difficulty of billing the B-party for calls charge at higher tariffs, as calls involving mobiles usually are).

Some mobile networks may offer reverse charge facilities via a customer services operator but such a service is likely to be offered in the home country only because of the difficulty of reverse charge accounting and billing across international networks.

Even if it were possible to access a customer service operator free of charge in a foreign country, and that mobile network had an interconnect agreement that

permitted reverse charge calling to the home country, language difficulties may make it hard for the user to achieve their objective.

For mobile pre-pay users, roaming is possible today on some networks. For example, on some networks USSD (Unstructured Supplementary Service Data) is used to alert the network that the user wishes to make an outgoing call whilst roaming.

USSD commands are intended for control of supplementary services and are passed through the network without charge. Certain classes of USSD commands are defined as being passed back to the home network, and so are ideal for this purpose. The user enters a particular USSD command into his handset and sends it to the network on which he is currently roaming. The command used may be one of the ETSI defined commands intended for a different purpose, or may be one of the reserved or undefined commands which are available.

When one of the home network HLRs (Home Location Registers) receives one of these commands from a roaming user, it initiates an outgoing call from the home network to the roaming mobile. As the call originates from the home network, billing and credit checking can operate successfully in the home network thereby preventing fraud problems. The user then receives the call back on his mobile and typically interacts with an automated announcement system to enter his desired destination number or service-the network then completes the call. Credit checking for the call then proceeds in the normal way, as for a call made from the home network.

An alternative way to alert the home network to the roamer's desire to use a service is the Short Message Service (SMS). Instead of sending a USSD message, the user enters an SMS message and sends it to a defined number in the home network. For this to be possible, the SMS service has to be enabled for the roaming user, which opens the possibility of the user being able to send SMS messages to other destinations when he does not have sufficient credit. This method is therefore less attractive than USSD.

According to the invention there is provided a telecommunications services apparatus for use with a mobile radio telecommunications system, said apparatus comprising: a controller for receiving a USSD (Unstructured Supplementary Service Data) signal from a mobile station of the mobile radio telecommunications system, and for identifying the USSD signal as a request for a reverse charge call involving a telephone number extracted from the USSD signal; and a call connection means for outdialling to said telephone number extracted from the USSD signal and for requesting acceptance of the reverse charge call, and for connecting said telephone number and said mobile station in response to an indication of acceptance of the reverse charge call, said call connection means also sending an identification signal characteristic of the telephone number of said mobile station to said extracted telephone number, said identification signal being derived from the signalling information provided by said mobile radio telecommunications systems in conjunction with the USSD signal.

A preferred embodiment of the invention provides a simple way of implementing a fully automated reverse charge system for mobile users.

The invention will now be described by way of example with reference to the accompanying drawings, throughout which like parts are referred to by like references, and in which: Figure 1 is a block diagram of a telecommunications services apparatus in accordance with an embodiment of the invention, comprising an automated reverse charge system; Figure 2 is a block diagram showing a network configuration of the automated reverse charge system; and Figure 3 is a diagram showing an implementation of the automated reverse charge system.

Referring to Figure 1, there is shown an automated reverse charge system comprising a call connection system and a controller. The call connection system provides communication to a user's mobile terminal, and also to a called party.

The preferred automated reverse charge system economically solves the problem of reverse charge calling within the home country, e. g. for young people with

pre-pay phones who wish to call home, and similarly enables roaming mobile users to make calls even when the available credit is zero.

Such a reverse charge service is most likely to find applications with pre-pay schemes, but could also be used for contract (post-pay) customers, for example, allowing employees to call their office free of charge from their own mobile phones.

The system uses the USSD scheme described above to enable a user (initiator) to indicate to the network that the user wishes to make a reverse charge call.

The USSD command sent by the user is basically of the form # < sc > * < telno > # where < sc > is the service code and < telno > is the telephone number which the user wishes to call (and to be billed for the call).

Other forms are possible, as the USSD specifications support a variety of similar formats.

The system, which is located within the home mobile operator's network, places a call to the destination (called party), indicated by < telno > . When the call is answered, the call connection system announces that the caller wishes to make a Reverse Charge call and asks whether the called party wishes to accept it. The called party is asked to press a specific DTMF key or key sequence to accept the call. The telephone number of the user (caller) is announced to the called party by speaking the individual digits.

If the recipient of the outdial call accepts reverse charging, the call connection system immediately dials back to the mobile handset, announces to the user that the reverse charge call has been accepted and then makes the connection between the two parties.

The system provides billing information in the form of Call Detail Records (CDRs) for both legs of the call. The CDRs are processed by the mobile network operator's billing system with both call legs billed to the call recipient.

Billing is simplest if the recipient is restricted to being another customer of the same network, but in principle the technique can be extended to include billing between networks.

In fact, the mobile network operator may choose to restrict the service so that the recipient must be on its network-this would encourage family members to all have phones on the same network, for example.

The preferred system may helpfully handle situations where the call cannot be connected for any reason. For example, the recipient may reject the call, there may be no answer or the number may be busy, and similarly when the return call is made to the call initiator it may not be possible to connect, e. g. if another incoming call is in progress or radio signal has been lost. In these and other cases, the parties are informed of the call progress.

Figure 2 shows a mobile station MS (1) of a roaming mobile user communicating with a roaming network comprising a base station transmission system BTS (2), a mobile switching centre MSC (3) and an international gateway IG (4). The roaming network is shown as communicating with the roaming user's home network, which includes an international gateway IG (5), a mobile switching centre MSC (6), a home location register HLR (7), and an automated reverse charge system ARC embodying the invention, the system including a service control function (8), an intelligent telephony switch (9) and an interactive voice response system IVR (10).

The home network also includes a credit database (11), a further mobile switching centre MSC (12) and a base station transmission system BTS (13) which can communicate with another mobile station MS (14).

In Figure 2, the roaming mobile user (1) wishes to make a reverse-charge call to a mobile user on the same home network. He sends a USSD message which is transmitted through the roaming and home networks to arrive at the service control function (8). The switch (9) calls the destination phone (14) via the MSCs (6,12) and the BTS (13). Upon answer, the IVR (10) announces the reverse charge call and

obtains the recipient's acceptance. If given, the switch (9) dials out to the initiator (1), the IVR (10) announces the call and the parties (1, 14) are then connected together.

At the end of the call, if the B-party (recipient) is a contract (post-pay) customer, the system produces CDRs for transfer to the network billing system.

However, if the B-party is a pre-pay customer, then it is necessary to check in the credit database (11) prior to calling the B-party that they have sufficient credit for a call. Then, during the call the remaining credit is monitored with imminent expiry warnings provided if appropriate and the call cleared down if credit expires. The credit database (11) is updated as appropriate.

Figure 3 shows a preferred embodiment of the core processing elements of the system. The HLR (7) is connected to a fast transaction converter, such as an Ocean fastTC (20) manufactured by Telsis Limited, and is able to forward USSD codes received from roaming mobiles to the fastTC (20). The fastTC (20) communicates with a call handling unit (21), such as an Ocean fastIP or fast SSP manufactured by Telsis Limited, over TCP/IP. The call handling unit (21) is able to make calls via El connections to the rest of the network via the MSC (6), and to interact with both calling and called parties using voice prompting and DTMF detection functions, which are integral to the call handling units. It is also able to communicate with credit and billing control systems such as the credit database (11). If credit runs out it is able to clear down the call.

ETSI has defined (in the GSM system, GSM 02.30 and GSM 02.90) a range of USSD commands and codes for control of specified supplementary services. In addition, ranges of code values are reserved for communication between a mobile handset and the home location register in the home network and the visitor location register in the visited network.

USSD commands take the form < operation > < service code > * < supplementary information > #

where < operation > is, for example * for service activation or registration # for service de-activation *# for service interrogation * * for service registration ## for service erasure

service code > is a 2 or 3 digit number < supplementary information is one or more strings of digits separated by *.

Network operators who have already implemented pre-pay roaming services based on USSD as described above have chosen different approaches. For example, one operator has chosen to use the service code 100 which is within the range allocated for communication with the HLR, whilst another operator has chosen to re-use code 33 (specified for control of Outgoing Call Barring) for this purpose.

The choice of actual USSD code to be used with the preferred system therefore lies with the network operator. It needs to choose the appropriate code that will enable USSD messages to be delivered to the system.

For the purposes of example, we shall describe use of the code 111, which is within the range reserved for communications with the HLR.

In the preferred embodiment the user sends the USSD command *111*01489885877# to request a reverse charge call to 01489 885877 On receiving this USSD code from a mobile handset, the HLR (7) forwards the command via the Ocean fastTC (20) which translates the message into TCP/IP and passes it to the Ocean call handling unit (21).

The Ocean call handling unit (21) needs to know the telephone number of the initiator's mobile (the MSISDN--Mobile Station ISDN number). The HLR (7) holds the MSISDN and can provide it when presented with the IMSI (International Mobile Subscriber Identity) which uniquely identifies the SIM (Subscriber Identity Module) in the handset. The IMSI is part of the USSD message and the HLR (7) can either look up the MSISDN and include it with the message sent to the fastTC (20) or alternatively, having received the USSD message, the fastTC (20) can interrogate the HLR (7) to determine the MSISDN from the IMSI.

The call handling unit (21) dials the destination number and, when the call is answered, solicits acceptance of the reverse charge call with an announcement of the form: Good morninglafternoonlevening Will you accept a reverse charge telephone call from a mobile phone, number 07802 354935, in France ? Ifyou are willing to accept the call please press 1.

Jf do not wish to accept the callplease press 0.

If the recipient accepts the reverse charge call, the call handling unit (21) will then initiate an outdial back to the initiator's mobile. This outdial must not be diverted to voice mail even if the mobile is set up to divert all calls. The diversion is avoided by setting correct parameters in the outdialled call signalling information, typically by using a number prefix which is passed through the MSCs and interpreted as an instruction not to divert the call. Unconditional call forwarding (CFU) can be bypassed in this way since it is implemented at the HLR, while conditional forwarding is implemented in the VLR (Visitor Location Register) which will be in the roaming network. CFU to voicemail is usually the only type of divert permitted for pre-pay users, as this prevents them from diverting calls to other numbers which would incur a call cost (e. g. international or other mobile numbers). However, post-pay users who use conditional diverts may need to turn them off whilst they use this service, as otherwise there is a small chance that one of the divert conditions will arise between the user sending the USSD message and receiving the call back. It is possible that the

system can interrogate the HLR to determine whether any diverts are set-up and if so inform the user by means of USSD or SMS messages or voice announcement.

Assuming the call is answered by the initiator, the call handling unit (21) announces that the reverse charge call has been accepted and then makes the connection between both parties.

Whilst the second leg of the call, back to the initiator's mobile, is being set up, the recipient may be provided with'please wait'announcements or music-on-hold. It is a fundamental feature of the system that the call handling unit (21) is able to provide different, independent audio to both the initiator and the recipient.

If the two legs of the call cannot be established for any reason, e. g. the recipient rejects the call, or numbers are busy or unanswered, then the parties are informed appropriately. This may be by voice announcements or, in the case of the initiator, by USSD or SMS message initiated by the system.

In some implementations, the system may attempt later to re-establish an abandoned call. This may be done automatically as a standard service feature or optionally at the request of the initiator. If, for instance, the recipient does not answer the call, when the initiator is informed they could be given the option to request another attempt some time later.

In some implementations, particularly when reverse charge calls may be made to fixed network phones which may not support DTMF (which would inhibit the recipient from pressing 1 or 0) the call handling unit may provide speech recognition facilities and invite the recipient to say yes or no (for example) to accept or reject the call.

In an alternative implementation, the network operator may offer a simpler method of initiating a reverse charge call. In this case the required telephone number is not sent as part of the USSD command but is entered later as part of an interactive dialogue with the call handling unit.

The choice of USSD command lies with the network operator but may be of the form: *111#

or *lll*n# where n is one or more digits that denote a reverse charge call request.

The command is passed to the system as in the preferred embodiment, but now the first call set up by the call handling unit is back to the initiating mobile. When the call is answered the user is greeted and invited to key in the required phone number (typically terminated by #).

The DTMF digits representing the number are collected by the call handling unit and the call to the recipient is then made. The dialogue with the recipient is as described above for the preferred embodiment. If the call is accepted then, after informing both parties, the two call legs are connected within the call handling unit and the call proceeds as above.

A service feature which could be offered as a result of this method of call set up is name announcement. When the initiator has entered the required phone number they are invited to speak their name. This is recorded within the call handling unit.

Then, when the announcement of the reverse charge call is made to the recipient it is of the form (with the caller's name replayed from the store):

Will you accept a reverse charge call from a mobile phone in France. The caller is'John Smith'.

This technique is likely to increase the chance of call acceptance as the recipient will obviously recognise a voice and name more readily than a mobile telephone number (especially as many people use handset memories to store numbers and therefore do not necessarily remember the actual numbers).

This method of implementing automated reverse charge calls may be less attractive to the network operator because there are costs associated with dialling back to the initiator which may not be recoverable if the call is not completed for any reason. If the initiator is roaming and is on hold for some time whilst the system attempts to gain acceptance of the reverse charge call, then the costs may be

significant. (Whilst there are also costs associated with unsuccessful call set ups in the preferred embodiment, they are likely to be lower as the call back to the roaming initiator is much later in the process).

On the other hand, this approach enables the network operator to more easily offer an enhanced service. For example, if the recipient is busy, does not answer or rejects the call, then the initiator can immediately be invited to enter an alternative number to call. This facility would increase the likelihood of successful call completion and hence revenue for the network operator. For example, the initiator may first attempt to place a reverse charge call to a fixed network number and if there is no answer, they may try a mobile number.

Alternatively, the initiator may be offered the option for the system to attempt to set up the call later, this time calling back to the initiator (as in the preferred embodiment) if reverse charge acceptance is obtained. Another option offered to the initiator may be to record a voice message which the system will later attempt to deliver to the recipient (provided that they will pay for it). The initiator could be provided with confirmation of message delivery by SMS or USSD.

A further option could offer the originator the ability to make one or follow-on calls when the first is completed. The system would detect that the recipient has disconnected and if the initiator is still connected a voice announcement and prompt would invite them to attempt another reverse charge call. Alternatively, the call handling unit may be programmed to detect a sequence of DTMF key presses from the initiator which would cause the call to the recipient to be disconnected and a follow-on call offered.

In some implementations the mobile network operator may wish to offer unconditional reverse charge call acceptance facilities. For example, parents may decide that they will always accept reverse charge calls from their children's mobiles, or a company may always want to accept calls from nominated employees.

In these cases, the system may include a whitelist capability within a database, such that for each mobile user there may be a set of destination numbers for which calls will be connected immediately, i. e. without inviting the recipient to accept the call. It is likely that, when the call is answered by the recipient, a brief announcement

from the system will indicate that it is a reverse charge call, before the initiator is connected.

In all embodiments (unless follow-on calls are offered) the call handling unit will automatically disconnect the other call leg when a cleardown is detected on one leg.

In some situations (typically when a call is terminated on a fixed network) a backward clear indication may not be received for several minutes or even at all depending on the destination network. The call handling unit could implement an activity detector to protect against this, clearing the call after a number of seconds of silence from both parties.

The system described uses a USSD command to request a reverse charge call.

It would also be possible to use SMS for the same purpose, although this may not be preferred because SMS messaging is not necessarily available on all foreign networks and also it is a'store and forward'system which means that there may be an (unacceptable) delay between transmission of the SMS request and its receipt at the system.

Claims (4)

CLAIMS 1. A telecommunications services apparatus for use with a mobile radio telecommunications system, said apparatus comprising: a controller for receiving a USSD (Unstructured Supplementary Service Data) signal from a mobile station of the mobile radio telecommunications system, and for identifying the USSD signal as a request for a reverse charge call involving a telephone number extracted from the USSD signal; and a call connection means for outdialling to said telephone number extracted from the USSD signal and for requesting acceptance of the reverse charge call, and for connecting said telephone number and said mobile station in response to an indication of acceptance of the reverse charge call, said call connection means also sending an identification signal characteristic of the telephone number of said mobile station to said extracted telephone number, said identification signal being derived from the signalling information provided by said mobile radio telecommunications systems in conjunction with the USSD signal. 2. Apparatus according to claim 1, including means for billing both calls from the call connection means to the acceptor of the reverse charge call. 3. A telecommunications services apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. CLAIMS Amendment to the claims have been filed as follows

1. A telecommunications services apparatus for use with a mobile radio telecommunications system, said apparatus comprising: a controller for receiving a USSD (Unstructured Supplementary Service Data) signal from a mobile station of the mobile radio telecommunications system, and for identifying the USSD signal as a request for a reverse charge call involving a telephone number extracted from the USSD ; and a call connection means for outdialling to said telephone number extracted from the USSD and for requesting acceptance of the reverse charge call, and for connecting said telephone number and said mobile station in response to an indication of acceptance of the reverse charge call, said call connection means also sending an identification signal characteristic of the telephone number of said mobile station to said extracted telephone number, said identification signal being derived from the signalling information provided by said mobile radio telecommunications system in conjunction with the USSD signal.

2. A telecommunications services apparatus for use with a mobile radio telecommunications system, said apparatus comprising: a controller for receiving a USSD (Unstructured Supplementary Service Data) signal from a mobile station of the mobile radio telecommunications system, and for identifying the USSD signal as a request for a reverse charge call; and a call connection means for outdialling to said mobile station inviting entry of the telephone number of the required reverse charge called party and, in response to entry of said telephone number, for outdialling to said telephone number requesting acceptance of the reverse charge call, and for connecting said telephone number and said mobile station in response to an indication of acceptance of the reverse charge call, said call connection means also sending an identification signal characteristic of the telephone number of said mobile station to said telephone number of the required reverse charge called party, said identification signal being derived from the signalling information provided by said mobile radio telecommunications system in conjunction with the USSD signal.

3. Apparatus according to claim 1 or claim 2, including means for billing t=l both calls from the call connection means to the acceptor of the reverse charge call.

4. A telecommunications services apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.