1. Field of the Invention
The present invention relates, generally, to a mobile station for use in mobile radio systems and, move particularly, to mobile telephones through which it is possible to transmit not only voice information but also text messages.
2. Description of the Prior Art
Mobile communication is one of the fastest growing segments in the futuristic, high-growth field of telecommunications. Various mobile radio systems and communication standards are already known. The so-called GSM mobile radio system (Global System for Mobile Communication) has been in use in Western Europe since 1992 and, since then, also has been introduced in a large number of countries outside Western Europe. The DCS-1800 mobile radio system (Digital Cellular System) is also known and is virtually identical to the GSM mobile radio system, except for the frequency band. Other known mobile radio systems and communication standards include the American D-AMPS mobile radio standard (Digital Advanced Mobile Phone System), which is also called IS-54 (Interim Standard 54). IS-95 mobile radio system is also currently used in the USA. The JDC mobile radio standard (Japanese Digital Cellular) is known in Japan and is also called PDC mobile radio standard (Personal Digital Cellular).
The known mobile radio systems and communication standards described above differ not only in the frequency band used but also in terms of other major technical parameters; such as the channel separation, the multiplexing method, the modulation method or the number of channels which can be transmitted per carrier frequency.
As a rule, mobile radio systems are of cellular design; that is, the overall area to be supplied is subdivided into relatively small radio zones, so-called radio cells, in which case each radio cell is assigned a base station whose reception area is limited to the corresponding radio cell. Thus, within a radio cell, a mobile terminal always communicates only with the base station responsible for that radio cell. If a mobile terminal moves out of the supply area of its base station, the connection has been routed via a different base station. This is done by automatically changing the radio zone without any significant disturbing influence on the quality of the call in progress. This process is called xe2x80x9chandoverxe2x80x9d.
In addition to the actual telephone service, that is to say the transmission of voice information, a number of mobile radio systems also offer additional services such as short message services, the transmission of teletext information, or the transmission of fax information.
The present invention now relates to mobile stations which are able to transmit the short messages mentioned above. With appropriately equipped mobile telephones, the user can, thus, compose a short text message and send it to a desired recipient. The text message may be stored in the mobile telephone itself; or on a smart card, for example, the SIM smart card (Subscriber Identity Module).
Within the GSM mobile radio system, this short message service is called the SMS. SMS is a new service, specifically for mobile radios, which has been introduced with the GSM. In this case, a mobile station can send text messages, such as traffic information, not only to an individual recipient but also to a number of receiver stations. According to the SMS Standard, the text messages to be transmitted may include up to 160 alphanumeric codes, in which case each character can be stored coded and packed by means of a 7-bit ASCII code.
The text messages are input via the keypad on the mobile telephone. Since a large number of individual alphanumeric characters have to be input and, as a rule, each key on the mobile telephone has multiple functions for inputting letters and numbers, the process of inputting a text message is complicated, tedious and not very user-friendly. If, for example, the number xe2x80x9c1xe2x80x9d is provided on a key in the fourth place after the letters xe2x80x9cABCxe2x80x9d, then, before inputting the number xe2x80x9c1xe2x80x9d, the appropriate function must be selected by operating this key several times. The process of inputting a long number, for example a telephone number, in a text message to be transmitted is thus, in particular, very onerous for the user.
EP 0 693 860 has already disclosed an SMS system which contains SMS messages which have been prepared in advance and which can be expanded by user-defined inputs. Embodiments of the invention described in the document are concerned with the conversion of these messages into other languages a in particular, languages having alphabetic characters which differ from latin alphabetic characters, such as Greek or Cyrillic characters.
The present invention is, thus, based on the object of refining a mobile station so as to make it easier for a user to transmit text information and text messages using the mobile station.
The mobile station according to the present invention has memory means for the storage of predetermined text information which includes at least one text field which cannot be changed by the user. This predetermined text information may include a number of predetermined text messages, which can be selected by a user as required. In the simplest case, the user merely has to select one of the predetermined text messages, without any need for the user to make any additional text inputs.
The present invention is, accordingly, not just limited to mobile telephones, but also can be used on mobile stations which can only transmit text information and/or can only transmit (and cannot also receive) communication information.
According, to a preferred embodiment of the present invention, however, the predetermined text information includes a plurality of text records or text messages in which each text message includes a number of text fields which cannot be changed by a user as well as a number of input fields which can be changed, as required, by the user. The user can use the keypad on the mobile station to add to a predetermined text message, as required, by inserting alphanumeric characters into a user variable input field in the appropriate text message.
The mobile station display allows the user to continuously monitor the selection of the text messages as well as the insertion of the alphanumeric text characters.
After selection of a predetermined text message, the user can operate appropriate keys on the mobile station keypad to change between the individual Muser variable input fields wherein the current insertion position preferably is shown on the display by means of a flashing cursor.
The predetermined text information stored in the memory means thus includes predefined text modules which a user merely has to add to. As such, the user need enter only a small amount of text which makes it considerably easier for the user to transmit and input text information.
A user variable input field in a selected text message may be either empty or already filled with predetermined characters. This can be accepted or overwritten by the user. An input field also may have the length 0 such that the input field displays only an insertion mark at the point where a user can input any desired text. The input fields may be of variable length and can be enlarged as required. However, since, for example in the case of the GSM mobile radio system, the maximum, length of a text message to be transmitted includes 160 characters, the present invention proposes that the instantaneous overall length of the text which is changed by the user should be monitored using an appropriate control device and that, if the maximum length is exceeded, any test characters that have been input in addition are rejected, or that lengthening of the text message is suppressed. In general, when an input field is enlarged, the subsequent text, that is to say the subsequent, fixed text fields as well as the subsequent user variable input fields, are shifted to the rear, or to the right.
According to preferred embodiment of the present invention, the individual user variable input fields are assigned specific predetermined field types so that only characters corresponding to the field type can be input into each input field in the format appropriate to the field type. Thus, for example, one input field may allow only numbers to be input while another may allow only letters to be input. Furthermore, in the former case, it is possible for one input field to allow numbers to be entered only in a data format or in a time format. The mobile station advantageously has a control device which uses the positioning of cursor in an input field to automatically identify the field type assigned to this input field and, when the mobile station keypad has multiple functions, to automatically activate that function which corresponds to the format of the corresponding field type. If, for example, one field type in an input field allows only numbers to be input, then the control device automatically activates that key function on the mobile station keypad which can be used to input numbers. This, on the one hand, automatically prevents letters from being input and, on the other hand, makes it easier to input numbers since the user does not need to operate the appropriate key several times.
The user also has the option, of course, of presetting and storing new text information and text messages himself. Information relating to any predetermined text message is, in this case, stored together with the predetermined text information which defines the number of user variable input fields, the position of the user variable input fields in the predetermined text message, the length of the user variable input fields and the type of individual input fields in the predetermined text message. This information is stored with each predetermined text message in the form of a xe2x80x9cheaderxe2x80x9d. The header, thus, includes all the necessary information relating to the user variable input fields and, therefore, represents a suitable format for storing the predetermined text messages in a data memory having a small memory volume. As such, the greatest possible flexibility is ensured. The administration of the input fields in the header allows the input fields to be found easily.
After selection of a predetermined text message or of a predetermined text record, the selected text message is shown on the display, preferably with the user variable input fields being marked and highlighted by displaying appropriate spacekeepers. In the same way, it is also possible to mark only the start and end of an input field by specific characters.
Although the present invention is not limited to this, the mobile station in the present invention is advantageously used in the form of a mobile telephone which can not only send, but also receive, text information and which, in addition, is suitable for the transmission of voice information.