Abstract:
A portable prepaid phone has a display, input means for inputting information and instructions, a control unit controlling the display in dependence on the operation of the input means, and transceiver means communicating via a wireless network controlled by a network operator. The network operator manages an account for said phone and updates the account upon the occurrence of a credit-affecting event. The network operator forwards a credit update message to portable prepaid phone and said message contains information about the current account and the credit affecting event causing the message to be sent to the phone upon the occurrence of a credit affecting event. In the phone the transceiver means receives the credit update message, the control unit decodes the received message in order to identify the content of the credit update message, and the control unit initiates the display of the current account in the display, immediately after the termination of the credit update message decoding.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The invention relates to prepaid phones. The operator has a database of accounts handling the credit of the respective phones. The user will be able to use the phone as long as the associated account shows a positive credit level. However the user may recharge the account by phone banking or by buying recharge cards and transferring the associated code to the network operator. 
     BACKGROUND OF THE INVENTION 
     The user has a possibility to check the credit level of his account by calling an interactive voice responder. The voice responder is free of charge and the network operator therefore loses free air time. Experience has shown that this loss will be in the level of one third of the total airtime. In order to get rid of this non-chargeable free air time it has been requested to design a network that transmits a credit update message immediately after the occurrence of a credit affecting event. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a portable prepaid phone being able to receive a credit update message from a network operator being forwarded upon the occurrence of a credit affecting event, said credit update message contains information about the current account and the credit affecting event causing the message to be sent, and to inform the user about the event. 
     This purpose is obtained by a portable prepaid phone having a display, input means for inputting information and instructions, a control unit controlling the display in dependence on the operation of the input means, and transceiver means communicating via a wireless network controlled by a network operator, said network operator manages an account for said phone and updates the account upon the occurrence of a credit affecting event, and said network operator forwards a credit update message to portable prepaid phone and said message contains information about the current account and the credit affecting event causing the message to be send to the phone upon the occurrence of a credit affecting event, wherein the transceiver means of the portable prepaid phone receives the credit update message, the control unit decodes the received message in order to identify the content of the credit update message, and control unit initiates the display of the current account in the display, immediately after the termination of the credit update message decoding. Hereby the user will be able to get the information by using a simple SMS transmitted to the phone. First of all bandwidth is saved and secondly phone will be able to store the information. 
     Preferably the control unit displays the credit information for a predetermined period of time—e.g 3-5 seconds. During this period the control unit may advantageously disable the input means. Advantageously an alert signal may be given by the alert signal means (e.g. a buzzer or a vibrator) in order to inform the user when certain events have occurred. 
     Preferably the processor stores all credit information received in credit information messages in a log file. This log file may have a limited maximum size, and when this size is reached a new entry will replace the oldest one. The user may be allowed to transfer the content of the log file to e.g. a PC by means of an IR link. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 schematically illustrates a preferred embodiment of a hand portable phone according to the invention. 
     FIG. 2 schematically shows the essential parts of a telephone for communication with a cellular or cordless network. 
     FIG. 3 shows a preferred embodiment of system architecture according to the invention. 
     FIG. 4 illustrates a preferred embodiment of the credit information message according to the invention. 
     FIG. 5 shows a flowchart in which the phone monitors whether a credit information message has been received. 
     FIG. 6 shows three images illustrating a “call” scenario of the prepaid credit displayed according to the invention. 
     FIG. 7 shows four images illustrating a “low charge” scenario of the prepaid credit displayed according to the invention. 
     FIG. 8 shows three images illustrating a “no credit” scenario of the prepaid credit displayed according to the invention. 
     FIG. 9 shows three images illustrating a “credit recharged” scenario of the prepaid credit displayed according to the invention. 
     FIG. 10 shows three images illustrating a “credit service charged” scenario of the prepaid credit displayed according to the invention. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     FIG. 1 shows a preferred embodiment of a phone according to the invention, and it will be seen that the phone, which is generally designated by 1, comprises a user interface having a keypad  2 , a display  3 , an on/off button  4 , a speaker  5 , and a microphone  6  (only openings are shown). The phone  1  according to the preferred embodiment is adapted for communication via a cellular network, but could have been designed for a cordless network as well. 
     According to the preferred embodiment the keypad  2  has a first group  7  of keys as alphanumeric keys, a soft key  8 , and a navigation key  10 . Furthermore the keypad includes a “clear” key  9 . The present functionality of the soft key  8  is shown in separate fields in the display  3  just above the key  8 . This key lay out is a characteristic of the Nokia 3110™ phone and the Nokia 5110™ phone. 
     FIG. 2 schematically shows the most important parts of a preferred embodiment of the phone, said parts being essential to the understanding of the invention. The preferred embodiment of the phone of the invention is adapted for use in connection with the GSM 900 MHz and GSM 1800 MHz network, but, of course, the invention may also be applied in connection with other phone networks. The processor  18  controls the communication with the network via the transmitter/receiver circuit  19  and an antenna  20  that will be discussed in details below. 
     The microphone  6  transforms the user&#39;s speech into the analog signals formed thereby are A/D converted in an A/D converter (not shown) before the speech is encoded in an audio part  14 . The encoded speech signal is transferred to the processor  18 , which i.a. supports the GSM terminal software. The processor  18  also forms the interface to the peripheral units of the apparatus, including a RAM memory  17   a  and a Flash ROM memory  17   b , a SIM card  16 , the display  3  and the keypad  2  (as well as data, power supply, etc.). The audio part  14  speech-decodes the signal, which is transferred from the processor  18  to the earpiece  5  via a D/A converter (not shown). 
     The preferred messaging concept. 
     According to the preferred embodiment this information is handled by the Smart Messaging Concept. This concept was disclosed by the applicant at the Cebit fair in Mar. 1997 (Press release Mar. 20, 1997) and discussed in details the document: “Smart Messaging Specification”, Revision 1.0.0; September being available on the Internet address URL: www.forum.nokia.com/nf/concepts/smart/main.html. From this Internet address another document “Narrow-Band Sockets Specification”, Revision 1.0, Mar. 7, 1997 may be downloaded. This document describes the Narrow-Band Socket (developed by a joint effort by of Intel and Nokia) that enables applications to access various network data bearer services using a standard socket interface. 
     The system architecture. 
     A preferred embodiment of the system architecture for managing the credit system is shown in FIG. 3. A Service Control Point  21  (SCP) in a so-called Intelligent Network (IN) contains credit information and a credit application for handling the credit of prepaid cards for cellular phones. A Home Location Register  25  (HLR) is a database including relevant subscriber information for the provision of the telecommunication service. An SS 7  Network  22  is a CCITT specified network interconnecting the individual parts of the system. A SMS gateway &amp; SMS interworking Mobile Switching Center (MSC)  23  is a switching unit routing a message or a call towards a Mobile Station (the phone  1 ). A Short Message Service Center  24  (SMSC) and a SMS gateway &amp; SMS interworking Mobile Switching Center (MSC)  23  handles and routes the SMS&#39;s between the SMSC  24  and the SS 7  Network  22 . From the SS 7  Network  22  the messages are routed towards the Mobile Station  1  via a Mobile Switching Center (MSC)  27 , and a Base Station Processor  26  (BSC). A Base Transceiver Station (BTS)  28  establishes the air connection towards the Mobile Station  1 . 
     This credit information is sent to the cellular phones when a predetermined event occurs. This is done by using the Smart Messaging concept. The short message&#39;s route is that the credit information is transmitted from the Service Control Point  21  via the SMS gateway  23  to the Short Message Service Center  24  where the message is generated in the correct format. From the Short Message Service Center  24  the message is routed via SMS interworking Mobile Switching Center (MSC)  23 , the Mobile Switching Center (MSC)  27 , the Base Station Processor  26  (BSC), the Base Transceiver Station (BTS)  28  before finally being received in the Mobile Station  1 . 
     The credit information message. 
     The format of the credit information message transmitted to the phone according to the preferred embodiment is illustrated in FIG.  4 . The message format is based on the Nokia/Intel Narrow Band Socket (NBS) specification. This format is already well known and used for a number of services already implemented in a wide range of Nokia products, e.g. Over The Air (OTA) business cards, OTA ringing tone download etc. 
     Basically a smart message  30  consists of a NBS header  31  and a message body  32 - 39  where the data is located. Preferably text based headers are used as in the existing Nokia OTA features. This header format will furthermore be compatible with the Wireless Application Protocol (WAP) according to the Wireless Datagram Protocol Specification, Version Apr. 30, 1998, available through the Wireless Application Forum Ltd. 
     The message  30  starts with the characters “//SCKL” identifying the NBS datagram addressing scheme to the receiving device (the phone  1 ) these characters are followed by the destination port (hexadecimal) that identifies the message type, e.g. //SCKL1583 (CLI logo download). A unique port address starting with “//SCKL” and followed by a predetermined or assigned four digit hexadecimal code is assigned for the credit information service. The phone  1  recognizes the address in the message header  31  the phone  1  deems the message  30  to contain credit information and handles the message accordingly. 
     The message body consists of a plurality of data fields  32 - 39  separated by line feed character. The first field  32  indicates the type of event that caused the message. The event types include: 
     Periodically update upon call (update). 
     Initial update when the phone  1  is switched on / access network. 
     Warning when the subscriber credit is below a predetermined limit (low credit). 
     Warning when the subscriber credit runs out (no credit). 
     Acknowledgement of recharged credit (recharge info). 
     Response of a user request (requested up date). 
     Information caused by charging the credit information service (credit information charge). 
     The message  30  does furthermore include a data field  32  identifying the date and time the short message were sent to the phone  1 , a data field  33  giving the phone  1  information about the current credit and a data field  34  containing information about the currency unit. Finally the message includes four data fields  36 - 39  containing information or being empty in dependence of the event. The first one  36  of these data fields contains information about the last call price and the second one  37  of these data fields contains information about the service charging price when a special service has been requested. The two last data fields  38  and  39  include information about the recharge time and the recharge amount, respectively. 
     FIG. 5 shows a flowchart in which the phone  1  in step  40  monitors whether a smart message has been received. When a smart message is received the processor  18  of the phone  1  checks the address part of the message in step  41  and if the processor  18  recognizes the message as being a credit information message, the processor  18  starts to look in the message header  31  in order to identify the event that caused the transmission of the message. If the message is not recognized as a credit information message the processor starts to identify the type in step  44  and to handle the message according to this. 
     When the processor  18  has identified the type of the event in step  42  it finds the current credit in data field  34  and displays the updated credit info in the display  3  of the phone  1 . The full credit information from the message is stored in a log file in the RAM memory  17   a.    
     When the network detects the event, e.g. a termination, it initializes the transmission of a smart message via the SMSC  24 . Therefore the user will receive the current credit information shortly after the event has happened. The current credit information can therefore be regarded as a pseudo real time indication. 
     According to the preferred embodiment the display of the credit information is accompanied by an alert signal (a beep) and the information remains in the display for a while (e.g. during a 5 sec. time out). 
     Different scenarios. 
     When the pre-paid phone is switched on the current credit, “KR 80,0” (80.00 Danish kroner) is displayed in the idle mode display as shown in the display  60  in FIG.  6 . The phone furthermore shows the clock “15:02”, the name of the operator “SONOFON”, that silent mode of the phone has been selected, and that the present functionality of the soft key  8  is “Menu”. The display  61  illustrates that a call is ongoing and that the soft key functionality is “End” (terminate call). The phone  1  receives a credit information message shortly after the call has been terminated and the new (current) credit is displayed in the idle mode display as seen in the display  62 . 
     FIG. 7 is actually a continuation of the scenario in FIG. 6 because the operator has a possibility to set a low charge limit, e.g. 75.00 dkr and when the account becomes under this limit the user is warned as shown in display  72  of FIG.  7 . 
     The message sent in the FIG. 7 scenario is a warning mess age indicating that the subscriber credit is below the predetermined limit. However this message includes the periodically updated information sent upon call termination. 
     The reception of the warning message will initiate the showing of updated current credit in the idle mode display  71 . However the warning due to the low credit will initiate two time outs where the display  72  will be displayed a few second later (the first time out) and will remain on the display for e.g. 3-5 seconds (the second time out). The occurrence of the warning display will be accompanied by an alert signal from the buzzer or the vibrator of the phone (none of these are shown but both will be well known for a man skilled in the art). After the run out of the second time out the idle mode display  71  will appear again. However when terminating the call during low charge the scenario of FIG. 7 will be repeated. The user can make calls as long as the account is in cr edit. 
     FIG. 8 illustrates a scenario according to which the network terminates a call (display  80 ) because there is no longer a positive credit on the account. A No Credit message is received and this initiates a time out (e.g. 3-5 seconds) during which the display  81  (“No Credit” explanation) indicates the lacking credit. After this the idle mode display  82  will inform the user about the “0,0” credit level. When the credit has run out only incoming calls and emergency calls are allowed. 
     FIG. 9 shows a scenario in which the display  90  corresponds to the display  73  in the low charge scenario. The user adds 100 DKr to his account, e.g. via an internet-based money transfer, or by transmitting a code obtained from a recharge card. This causes a credit recharged message initiating a time out during which the user is informed in the display  91  that the account has been recharged with 100 DKr. After the time out the e up-dated current credit is shown in the idle mode display  92 . Upon the occurrence of the recharging information in the display  91  the phone outputs an alert signal. 
     The FIG. 10 scenario shows that a special service has been charged. This service can be a software download, e.g. some graphic animation for the display. The display  10  corresponds to the display  92  in the recharge scenario. When the phone receives a “credit service charged” message this causes the initiation of a time out. During the time out the display  101  informs the user that the account has been charged with 50 DKr due to a credit service charge. The new current credit is shown in the idle mode second display  102 . Upon the occurrence of the charging information in the display  101  the phone outputs an alert signal. 
     Preferably during the 3-5 seconds time out after the alert signal has indicated a special event causing a current credit update the processor  18  disables the phone keypad.