METHOD IN A COMMUNICATION SYSTEM
TECHNICAL FIELD OF THE INVENTION
The invention relates to a method in a communication system comprising a service executing entity and a wireless terminal. More specifically the invention relates to a method for communication between the service executing entity and a user of the wireless terminal during execution of a "value added service" procedure by the service executing entity.
DESCRIPTION OF RELATED ART
Wireless terminals, such as mobile phones or DECT-phones, are known to include a phone book feature. This feature enables the terminal user to maintain a list of persons and their phone numbers, i.e. directory numbers. An outgoing call to a person included in the list can be made by specifying the persons name on the keypad to retrieve the persons phone number and then the retrieved phone number is used to call the person. When an incoming call is received by the wireless terminal, an air interface message, e.g. the TIA/EIA IS-136 Alert with Info message, typically includes a calling party number field containing the directory number of the calling party. The wireless terminal reads the received directory number of the calling party in order to detect a match with the entries in the phone book list. If a match is found, the name associated with the directory number is displayed on the terminal display.
WO 98/28903 describes a communication system for providing charge rate support to cellular pay/debet phones. The system calculates a charge rate for a call being made by a cellular pay/debet phone and sends it to that phone using a standard air interface message in a non-standard manner, e.g. by using either a Calling Party Number or Voice Message Waiting field to transfer the charge rate information. This message allows the pay/debet phone to determine the charge rate.
WO 98/28903 also teaches how an "Advice of Charge" service can be implemented without requiring modifications to existing mobile phones by transferring the charge rate information as readable characters in the Calling Party Number of an TIA/EIA IS-136 Flash with info message utilizing the existing well known mechanism in the phone of displaying the characters received in the calling party number field.
SUMMARY OF THE INVENTION
The problem dealt with by the present invention concerns the providing of communication between a service executing unit in a communication system and a user of a wireless terminal in the communication system.
The problem is solved essentially by a method wherein the service executing unit initiates transfer of an air interface message containing a display code in a calling party number field to the wireless terminal when the service executing unit, during execution of a value added service procedure, needs to communicate with the user. The wireless terminal uses the display code in the air interface message to select and display a text string stored in the wireless terminal.
More specifically, the problem is solved in the following manner. When the service executing unit, during execution of the value added service procedure, reaches a state in which communication with the terminal user is required, the service executing unit initiates transfer of the air interface message containing the display code in the calling party number field to the wireless terminal. The display code is distinct from any valid directory number. Upon receiving the air interface message at the wireless terminal, the text string is retrieved after determining that the display code matches a key value stored in the wireless terminal and associated with the text string. The text string, which is a message reflecting the state reached in
the execution of the value added service procedure, is displayed on the display of the wireless terminal.
An advantage provided by the invention is that the user of the wireless terminal may customize the text strings being displayed.
Another advantage is that by transferring only a display code, less data is transferred over the air interface as compared to if transferring a complete text string of readable characters.
The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a view of a communication system.
Fig. 2 is a flowchart illustrating a scenario where the user wishes to alter the setting of a subscriber service.
Fig. 3 is a signalling diagram illustrating exchange of signals in the scenario of Fig. 2.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Fig. 1 is a view of a communication system 101 in which the present invention is applied. The communication system comprises a cellular network 102 having a network structure conforming to the TIA/EIA IS-41 specifications and using an air interface according to the TIA/EIA IS-136 standard. Note that the invention is in no way limited to be applied only in communication systems containing TIA/EIA IS-41 and IS-136 conformant cellular networks, but may on the contrary be applied in connection with many different kinds of radio communication networks such as GSM, PDC, NMT, TACS etc. The cellular network
102 comprises a home location register (HLR) HLR1. The cellular network 102 further comprises a first mobile switching center
(MSC) MSCl and a second mobile switching center MSC2. Both mobile switching centers MSCl, MSC2 depicted in Fig. 3 are assumed to include visitor location registration (VLR) functionality, i.e. the nodes MSCl and MSC2 comprises both the Mobile Switching Center and the Visitor Location Register functional entities defined in TIA/EIA IS-41. A first set of base stations BS1-BS2 are connected to the first mobile switching center MSCl and provide radio coverage in a geographical area served by the first mobile switching center MSCl. A second set of base stations BS3-BS5 are connected to the second mobile switching center MSC2 and provide radio coverage in a geographical area served by the second mobile switching center MSC2. The first mobile switching center acts as a gateway mobile switching center (GMSC) and interconnects the cellular network 102 with other networks such as e.g a public switched telephone network (PSTN) . Since the network elements described above are all well known to a person skilled in the art, the general function of each of these network elements will not be further described. In addition to the cellular network 102, the communication system 101 also comprises at least one mobile station MSI. A user of the mobile station MSI can access telecommunication services and value added services offered by the cellular network 102 via the mobile station MSI. The term "value added service" is synonymous to the term "supplementary service" as defined in the ITU I-series recommendations, i.e. it is not a basic communication service (bearer or teleservice) but a service providing added value to basic communication services as for example a call transfer or a call screening service.
A number of different value added services are implemented in the home location register HLR1, i.e. the home location register HLR1 acts as a service executing unit as value added service procedures are executed. During the execution of most value added service procedures, the home location register HLR1 must communicate with a mobile station user, such as the user of the
mobile station MSI. The present invention relates to a method of providing said communication.
According to the invention, when a service executing unit, such as the home location register HLR1, during the execution of a value added service procedure reaches a state requiring communication with a user of a wireless terminal, such as the user of the mobile station MSI, the service executing unit initiates transfer of an air interface message containing a calling party number field to the wireless terminal. The calling party number field contains a display code distinct from any valid directory number. Upon receipt of the air interface message, the wireless terminal retrieves a text string being stored in the terminal and which is associated with a key value matching the content of the calling party number field, i.e. the display code. The text string, which is a message reflecting the state reached in the execution of the value added service procedure, is displayed on a display of the wireless terminal.
The display code may have a format identical to directory numbers, but an important property of the display code is that it is distinct from any valid directory number. Thus it may e.g. be that certain number series are not allocated for use as directory numbers but are instead used as display codes.
Preferrably the wireless terminal is a wireless terminal having conventional phone book functionality and the text string and its associated key value are stored as part of the phone book. By using the conventional phone book functionality, which automatically detects a match between the content of a calling party number field received in an air interface message and the entries of the phone book and displays a text string stored as part of the matching entry, the inventive method can be implemented without any impact on the wireless terminal.
One example of a typical situation where the inventive method may be applied, is when the service executing entity during
executing of a value added service procedure reaches a state requiring input from the user. As described above, the service executing entity initiates transfer of an air interface message containing an appropriate display code in the calling party number field, the wireless terminal receives the air interface message and uses the display code to retrieve a text string, which in this situation is a message prompting the user to provide a response. The wireless terminal detects a user response, typically via a keyboard on the wireless terminal, and the service executing unit is informed of the response from the user and continues execution of the value added service procedure in accordance with the user response.
Another example of a typical situation where the inventive method may be applied, is when the service executing entity shall report the outcome of execution of a value added service procedure to the wireless terminal user.
Fig. 2 and Fig. 3 provide a detailed example scenario of how the method according to the invention may be applied in the execution of a value added service procedure. In this scenario the user of the mobile station MSI illustrated in Fig. 1, wishes to alter the setting of a value added service such as e.g. inactivating "call transfer immediate". For subscribers, such as the user of the mobile station MSI, whose subscription data is managed by the home location register HLR1, the home location register also acts as a service executing unit for all service procedures related to e.g. the value added service "call transfer immediate". As a person skilled in the art recognizes, instead of allocating execution of the service procedures related to the "call transfer immediate" service to the home location register HLR1, execution of these procedures may be allocated to other network nodes such as e.g. a service control point (SCP) in an intelligent network.
At step 201 in Fig. 2, the mobile station MSI receives an input action from the user indicating that the user requests
inactivation of "call transfer immediate". The user thus dials a feature code string, e.g "#21#", requesting the mobile station
MSI to transmit this feature code string to the cellular network
102. At step 202 the mobile station MSI transmits a TIA/EIA IS-136 originating message, S31 in Fig. 3, to the second mobile services switching centre MSC2 via the base station BS5. The originating message S31 contains the dialled feature code string in a called party number field. The second mobile services switching centre MSC2 recognizes the content of the called party number field as a feature code string. The second mobile services switching centre MSC2 determines that subscription data for the user of the mobile station MSI is registered at the home location register HLR1 and forwards at step 203 the feature code string to the home location register HLR1 in a feature request signal S32.
Upon receiving the feature request signal S32, i.e. when the home location register HLR1 is informed of the users request, the home location register HLR1 initiates execution of a value added service procedure at step 204. The service procedure inactivates the call transfer immediate service for the user.
Upon completion of the service procedure, the home location register HLR1 shall communicate to the user a message indicating the outcome of executing the service procedure, i.e. a confirmation that the call transfer immediate service has been inactivated. Thus at step 205 the home location register HLR1 sends a feature response signal S33 to the second mobile services switching centre MSC2. The feature response signal contains a confirmation display code used for acknowledgment of a successful inactivation of the "call transfer immediate" service. Upon receiving the feature response signal S33, the second mobile services switching centre MSC2 transmits a TIA/EIA
IS-136 Flash with info standard message S34 to the mobile station MSI at step 206. The Flash with info message S34 conveys the specific display code in a calling party number field CPNl
contained in that standard message. Upon receipt of the Flash with info message S34, the mobile station MSI reads the display code from the calling party number field CPNl. At step 207 the mobile station retrieves a text string TXTl being stored in the mobile station MSI and which is associated with a key value Kl matching the transmitted display code. The text string TXTl matching the display code may in this example read "call transfer immediate inactivated" or the like. At step 208 the text string TXTl is displayed on the display of the mobile station MSI.