WO2011004207A1

WO2011004207A1 - Method and system for compressing short messages, computer program and computer program product therefor

Info

Publication number: WO2011004207A1
Application number: PCT/HU2010/000078
Authority: WO
Inventors: Tibor Ratkay; Norbert Kis
Original assignee: Metáll-Print Kft.
Priority date: 2009-07-10
Filing date: 2010-07-07
Publication date: 2011-01-13
Also published as: HUP0900432A2; HU0900432D0; WO2011004207A4

Abstract

A method for compressing short messages. The message is composed of at least one message element of a first type and at least one message element of a second type. At least one message element set containing a plurality of message elements of the first type is predefined, each of said message elements of the first type being associated with a code. During generation of the message, the user is prompted to select at least one message element of the first type (S104) and to input at least one message element of the second type (S112), in an arbitrary order. After generation of the message, said message element of the second type is compressed by using a compression technique selected by the user (S122).

Description

Method and system for compressing short messages, computer program and computer program product therefor

The present invention relates to a method and a system for compressing short messages, as well as to a computer program and a computer program product therefor.

Communication based on the transmission of short messages, in particular short text messages, is commonly used in almost all fields of the life, in particular in the field of mobile communications. The most common mode of sending short messages is transmission of SMS messages in mobile telecommunication networks. The content of the short messages may be diverse, including, for example, personal content, financial news, transaction notifications, daily, business or sport news, transmission of patients' data in medical applications, prompt (automatic) emergency messages, alarm for maintenance, remote measurement, remote data acquisition; electronic purchase (bus ticket, cinema ticket, concert ticket, entrance ticket for sport events); direct marketing, special promotions, product feedbacks, etc.

The SMS service, which is the most common way of transmitting short messages, provides substantial limitation for the length of the messages. In case of using the character representation defined by the Unicode standard (wherein the length of a message has an upper limit of 70 characters), although this representation is suitable for sending information by using the correct characters in a linguistic sense, the transmitted information or messages are very short, thus their information content is also very limited. In practice, another commonly used procedure is the transmission of messages according to the GSM 03.38 standard, which allows the use of up to 160 characters in a message. Although this standard uses a seven-bit character representation, this character set does not contain several characters specifically used by languages applying Latin letters, and therefore it may occur that the text transmitted in an SMS message contains grammatical errors or even it content might be confusing.

In the currently applied SMS standards, messages are adapted for the transmission of relatively low amount of data, and although longer messages that cannot be transmitted in a single short message may be transmitted in several related short messages, such a message transmission, however, incurs extra costs.

The document US 2006/0142997 A1 discloses a mobile terminal adapted for compressing text messages, said mobile terminal comprising a display, a text input device, a predictive editor application and a further software that by means of the predictive editor application, replaces at least a part of the words of the entered text with references to corresponding elements of a language specific vocabulary in the output data set. In the output data set, words and other character chains that are not included in the language specific vocabulary are inserted by the mobile terminal without encoding the output data set. The data amount of the thus obtained compressed output data set may be substantially lower than the data amount of the original text. A drawback of this approach is that words or other character chains not included in the vocabulary are added to the output data set without encoding. A further drawback is that compression of a text message to be transmitted is performed by using only one kind of compression technique (which is a word-based compression in this case), which does not allow an efficient compression, in particular for short text messages, in which the transmission of longer text elements and sentences with identical or substantially identical content is common.

It is an object of the present invention to eliminate the above drawbacks and to provide a method, a system and a computer program for compressing short messages, in particular short text messages or short messages partly including text, in a more efficient way than before.

It is another object of the present invention to provide a compression method and system wherein the compression is carried out in an interactive way with taking decisions of the user who is about to send a message into account.

Yet another object of the present invention is to provide a language independent encoding scheme for text data included in the message to be transmitted, and also to present said text data, in the device receiving the message, in a selected language in the form of a text containing the same information as the original message, and wherein the characters are presented correctly corresponding to the selected language.

The present invention is based on the inventive idea that in most cases, short text messages contain both of frequently repeated message elements (for example sentences, image elements, audio contents, etc.) having a length commensurable to the length of the user data field of the short messages and message elements, typically text elements, that are substantially shorter than the length of the message (for example, abbreviations, words, etc.). Combining different compression techniques for these two kinds of message elements, wherein each compression technique is optimized for the respective type of message element, results in a much efficient compression of such short messages.

The above objects are achieved by providing a method for compressing short messages, in particular short text messages or short messages partly including text, wherein the message is composed of at least one message element of a first type and at least one message element of a second type, the number and the order of said message elements of the first type and said message elements of the of the second type being arbitrary, and wherein at least one message element set containing a plurality of message elements of the first type is predefined, each of said message elements of the first type being associated with a code. The method further comprising the steps of

— predefining at least one compressing technique for the message element of the second type,

— during generation of the message, prompting the user to select at least one message element of the first type and to input at least one message element of the second type, in an arbitrary order,

— during generation of the message, temporarily storing at least one code associated with said at least one selected message element of the first type, and the at least one input message element of the second type in the order applied by the user, and

— after generation of the message, compressing the at least one temporarily stored message element of the second type according to a compression technique selected by the user, thus producing a compressed output data set containing the codes of the message elements of the first and the second types. - A -

The above object are also achieved by providing a compression system for compressing short messages, in particular for short text messages or short messages partly including text, the system comprising

— at least one message element set containing a plurality of predetermined message elements of a first type, each of said message elements of the first type being associated with a code,

— at least one predetermined compression technique,

— message editing means for generating said message from at least one message element of the first type selected by the user and at least one message element of the second type input by the user,

— message element browsing means for selecting at least one message element of the first type from said at least one message element set during editing of the message, and

— data compressing means for replacing, during editing of the message, said message elements of the first type with their associated codes and for compressing, after editing of the message, said message elements of the second type by applying a compression technique selected by the user, and thus for producing a compressed output data set.

The aforementioned objects are further achieved by providing a computer program that contains instructions which, when being executed on a computer or other device having a processor, carry out the method according to the invention.

Finally, the above objects are achieved by providing a computer program product which is stored in a data storage medium readable by a computer or any other device having a processor, said computer program product comprising instructions which, when executed on a computer or another device having a processor, carry out the method according to the invention.

The present invention will now be described in detail through non-limiting embodiments thereof, with reference to the accompanying drawings, wherein

Figure 1 is a flow diagram illustrating the basic steps of a preferred embodiment of the method according to the invention,

Figure 2 illustrates an example for a message header used in a preferred embodiment of the method according to the invention, and

Figure 3 is a functional block diagram of a preferred embodiment of the system according to the invention.

One of the important features of the method according to the present invention is that the message to be transmitted is composed of at least two kinds of message elements by using a message editing application, i.e. a message is composed of at least one message element of a first type and at least one message element of a second type. It should be noted that in the present description and the claims, the terms "first", "second" and "third" used to distinguish the message elements are only used to indicate the type of the respective message element and not to define a logical order of the message elements during generation or editing of the message.

The message elements of the first type are preferably message elements containing at least two characters, although they may also be audio data, still or moving image data (wherein the number of bits representing these letter media elements typically corresponds to a few hundreds of characters). Although it is preferred that the message element set containing the message elements of the first type contains mainly text message elements (or alternatively, only text message elements), other applications may also be envisaged wherein a message element set contains only media elements (for example, only audio files).

The message elements of the first type are stored in at least one predefined message element set stored in the user's device, wherein a so called "replacement code" is associated with each message element of the first type, said replacement codes generally having a substantially smaller bit length relative to the original bit length of the respective message elements. It is preferred that the predefined message element set contains words, groups of words, or complete sentences that are identical to or have similar content as words, groups of words or sentences that are frequently used in short messages in the communication between humans or between a human and the machine. The predefined message element set may, however, contain not only text elements, but also frequently used audio data (for example, ring tones, other audio effects) or image data (for example, logos, graphical symbols, photos, motion pictures). Hence, the predefined message element set contains frequently used message elements with higher bit length, wherein by replacing such message elements with the respective replacement codes, a significant compression rate may be achieved. In the method according to the invention, the message element to be transmitted by the user may be selected from the predefined message element set by the user himself. In order to make this selection easy, the message elements of the message element set are preferably stored in a structured manner. The predefined message element set may be structured according to, for example, topics, alphabetical order, frequency of occurrence of the elements, etc.

Since the message elements of the first type are predefined data that are stored in the user's device in advance, such message elements can be added to the message or can be removed from the message only as one unit during generation or editing of the message, i.e. the message elements of the first type added to a message cannot be modified during editing of the message.

The text message elements stored in the predefined message element set are stored in a vocabulary in at least one language. In a preferred embodiment of the method according to the invention, message elements of the predefined message element set with a given information content may be provided for the users in more than one language, thus the predefined message element set may have even a plurality of instances at the same time, each instance being defined in a different language but with the same information content. In such a case the system may actually contain several message element sets in which the same replacement code is assigned to the message elements (text, audio, still image, motion picture message elements) that are represented in different languages but have the same information content.

Thus it will be possible to present the text message elements of the first type in another language that is different from the one used at the generation of the message (interpreter function). At the same time, the use of language independent replacement codes allows for every user to store only one message element set corresponding to his own language in his device, although it is also feasible that a particular user may store even more versions of a message element set in different languages in his device and may than use any one of them.

The replacement codes of the message elements of the first type selected by the user form the predefined message element set during generation of the message are immediately added to a temporary data set after the selection of the respective message elements, wherein said temporary data set is stored in a temporary buffer during editing of the message. Consequently, the message elements of the first type are compressed and stored in the temporary data set in the form of replacement codes as early as during generation of the message.

An important and novel feature of the invention is that the text or non-text message elements of the first type of any length may be replaced with generally much shorter replacement codes, on the one hand, and the message elements of the first type to be compressed are compressed as early as during generation of the message by adding the respective replacement codes of the message elements to the temporary data set, on the other hand. Due to the aforementioned feature, with respect to the message elements of the first type, taking the average of a large number of transmitted messages, a substantially more efficient compression may be achieved than ever before.

In the method according to the invention, depending on the bit length of the selected replacement codes, the average bit compression rate of the message elements of the first type belonging to the predefined message element set is typically at least 2:1 , preferably at least 5:1 when regarding the whole message element set. Thus in a given message, the average bit compression rate of the included message elements of the first type is typically at least 2,5:1 , which means that in the temporary data set, the aggregate bit length of the replacement codes of the message elements of the first type is typically at least 40% of the original aggregate bit length of the message elements of the first type added to the message. Obviously, depending on the content of a given message, a compression rate having a substantially higher value than the typical value of the minimum bit compression rate may usually be achieved, however, in a very rare case, a bit compression rate of only approx. 2:1 or even lower might be resulted for the message elements of the first type with respect to all of the message elements of the first type of the particular message. This latter case may occur when a message contains a relatively large number of rarely used message elements of the first type that are thus represented, for example, by longer replacement codes, or when the message contains a relatively large number of very short but frequently used text message elements (for example "Hi!", "OK", etc.).

The length of the replacement codes may be fixed, but replacement codes with variable length may also be used. In this latter case, it is preferred that the message elements of the first type that are used more rarely or those that have larger bit length (for example special words, longer sentences, etc.) are associated with replacement codes of higher bit length.

As the predefined message element set contains predefined message elements (for example sentences, phrases), during generation of the message the user may not always be able to find the appropriate one among those that have the same or substantially the same information content as the information to be transmitted by the user. In such a case, the user may add such information to the message in the form of a message element of the second type. The message elements of the second type that can be only text data, including typically names, abbreviations, symbols, specific or rarely used words, groups of words, sentences, etc., can be added to the message in the form of subsequent text characters. In this context, a text character is referred to as a character that can be presented in a text field of a display device, including, in particular, alphanumeric characters, punctuation marks, mathematical and other graphical symbols, standard signs, etc.

During generation of a message, the message elements of the second types are stored in the temporary buffer without compression in a character based representation.

A message generated by using the method according to the invention may contain any number (but at least one) message element of the first type and any number (but at least one) message element of the second type, wherein the message elements of the first and second types may be added to the message in any order.

In the particular example below, it will be illustrated how a given message is represented in the message editor and in the temporary buffer. In this example, it is assumed that the user writes the message in Hungarian language and to this end, during editing of the message the message elements of the first type are selected from the Hungarian language elements of the predefined message element set.

The message editor displays the Hungarian language message (translated into English) to be transmitted in the following form: <Good morning!> <l am sorry, just a moment ...> <Let me introduce to you.> <My name is> Tibor. <My car has been forced. > <l would like to call the Hungarian Embassy.> <Where is the closest police station?> .... ??? .... <You are very kind.> <Thank you and sorry for having disturbed you.>

In the above representation the marks < > are used to indicate the message elements of the first type, each of which is handled as one unit of text by the message editor. In the temporary buffer, the above message is represented in the following form:

replacement code 1> replacement code 2> replacement code 3> replacement code 4> Tibor. replacement code 5> replacement code 6>

< replacement code 7> .... ??? .... replacement code 8> replacement code 9>

If in the device used to decompress the above message, the Spanish language is set as the language for the presentation of the messages, then assuming that the predefined message element set stored in the particular device also contains the Spanish message elements corresponding to the respective replacement codes, the message will be presented in the display of the device in the following form:

<jBuenos dϊas!> <Perdόn, un momento...> <Permitame que me presenter <Me llamo> Tibor. <Me han forzado el coche.> < Quisiera llamar a Ia Embajada de Hungrιa.> <_<<,Dόnde esta Ia comisaria mas cercana?> .... ??? .... <Usted es muy amable.> <Gracias y discύlpeme por Ia molestia.> If during editing of the message a message element of the first time is deleted, the entire message element of the first type, i.e. the entire text between the marks < > in the display of the device will be deleted, whereas the replacement code corresponding to the particular message element of the first type will be removed from the temporary buffer.

Since the message elements of the second type are stored in a character based representation, the characters to be deleted from the message during editing of the message are removed from the temporary buffer also on a character basis. The message elements of the second type are also subject to compression, but only after generation (editing) of the message. The message elements of the second type stored in the temporary buffer in the form of characters are preferably compressed by a specific compression technique actually selected by the user (or set by the user as default) which compression technique is preferably a language specific, frequency-based compression technique. The substance of such a compression technique is that each character or each predefined group of characters of the message elements of the second type are replaced by a bit sequence of variable length that is pre-stored in a code table belonging to the particular compression technique. The codes of variable length may be generated, for example, by the Huffman algorithm. In case of the message elements of the second type, which contain text characters, the compression rate that can be achieved by using the aforementioned code tables is generally much lower than the compression rate achievable for the message elements of,the first type. Due to the language specific code tables, it is possible to replace the characters of the message elements of the second type with codes of variable length optimized on the basis of the occurrence frequency of the characters of the language used by the user who is about to send the message, whereby independently of the language that is used for inputing the message elements of the second type, the statistically shortest sequence, regarding the whole message, will be generated in the step of compression of the message elements of the second type.

For the compression of the message elements of the second type, however, any other code table with codes of variable or fixed length, as well as code with reduced or complete character set may also be applied.

In the method according to the invention, during compression of the message elements of the second type, any one of the following compression techniques may be preferably chosen:

a) Compression on the basis of the character frequency of the language, wherein the characters of the code tables are represented by 3 to 64 bits.

b) Compression on the basis of the most frequent character groups of the language, wherein one character group includes 2 to 50 characters. c) Compression on the basis of the entire character set of the language, wherein the letters and punctuation marks of the alphabets used nowadays together with the old characters of the language are represented by 3 to 64 bits.

d) Compression on the basis of a unified character set, wherein the unification or the collection of the languages may be based on the languages of ethnical groups living close to each other, the geographical location of the languages, etc., and wherein in the code table, all of the characters included in the languages belonging to the particular group are represented by 3 to 64 bits.

e) Other text compression technique with loss of information (for example, eliminating the distinction between small and capital letters, eliminating accents, application of other redundant character sets, eliminating spaces, etc.)

With regard to the aforementioned compression techniques, the bit compression rate achievable for the message elements of the second type represented by text characters in a short text message is much lower than the bit compression rate that can be achieved for the message elements of the first type. By using the frequency based compression techniques applied in the method according to the invention, the practically achievable bit compression rate is typically within the range of approximately 1 ,2:1 to 1 ,05:1 , that is as a result of such a compression, the original aggregate bit length of all individual characters added to the message by the user can be reduced typically by 5 to 15%. Although such a bit compression rate of the message elements of the second type contained in the messages is relatively low and it provides a much lower compression efficiency in comparison with the bit compression rate of the message elements of the first type of the particular message, in many cases, due to the preset fixed length of the pay-load field of the standard messages, a save of a few bits might even result in a significant cost reduction. Although the most efficient compression of the message elements of the second type may be reached by the use of codes of variable bit length, for certain applications, some embodiments of the method according to the invention may use a code table of codes having fixed length for the compression of the message elements of the second type (even with the loss of information).

From the above features, it can be established that the average bit compression rate for all message elements of the first type of the predefined message element set (i.e. the ratio of the average bit length of all predefined message elements of the first type and the average bit length of the replacement codes associated with the message elements of the first type) is substantially higher than the average bit compression rate of all possible characters supported by the compression technique chosen for the message elements of the second type (i.e. in case of a particular compression technique, the statistical ratio of the aggregate bit length of the original characters transmitted in the message and the aggregate bit length of the character codes assigned to the original characters).

With regard to the situation where a short message may also contain characters that cannot be found in the code table of the compression technique selected by the user, and with regard furthermore to that a short message may also contain message elements that are stored in the user's device already in a compressed form (such message elements typically include individual audio files, individual image data added to the message by a user that are generally stored in the user's device as, for example, mp3, mp4, jpg, gif, etc. files), in a preferred embodiment of the method according to the invention, such data are added to the message in the form of message elements of a third type, wherein such message elements of the third type are also stored in the temporary buffer without modification. The message elements of the third type are, however, not subject to subsequent compression, that is these message elements are added to the compressed output data set in their original representation. In a preferred embodiment of the method according to the invention, during generation of the message, the replacement codes corresponding to the message elements of the first type, the compressed message elements of the second type and, optionally, the unchanged message elements of the third type in the temporary buffer, as well as in the output data set (after compression of the message elements of the second type) are separated from each other by appropriate flag bits, wherein preferably, the flag bit groups associated with the various message elements are inserted preceding the respective message elements in the output data set. The aforementioned flag bit groups clearly define the type of the message elements associated therewith. For the separation of the data corresponding to the subsequent message elements in the temporary buffer, any other suitable method may also be chosen.

As the final step of the compression, at least a piece of information suitable for identifying the compression technique selected for the compression of the message elements of the second type is associated with the output data set, wherein such a piece of information may be accommodated in a header attached to the output data set. This identification information may be represented by a field of predefined bit length. In case the output data set is to be transmitted as data embedded in a standard data transmission message, such as in the pay-load field of an SMS message, the aforementioned header, at its starting position, may also contain a special bit sequence that indicates the application of the compression method according to the invention.

The aforementioned header may further comprise an additional field describing the length (bit number) of the compressed data set, and optionally, even other fields containing further information.

In case of transmitting the compressed output data set in a standard data transmission message, in a preferred embodiment of the method according to the invention, it is preferred that a special bit sequence indicating the application of the method according to the invention be inserted to inform the device receiving said message that it should pass the data of the pay-load field of the standard message received by the particular device to a decompressing routine corresponding to the compression method according to the invention that is capable of recovering the original content thereof. In a preferred embodiment of the method according to the invention, two groups are defined for the methods used to compress the message elements of the second type; the first group includes frequently used compression techniques, whereas the second group includes compression techniques that are used less frequently. Accordingly, the techniques belonging to the first group are identified by a shorter bit sequence than the techniques of the second group. The techniques of the first group, typically the techniques used in the most commonly spoken languages or the most efficient techniques, are identified, for example, by a 10 bit code (2¹⁰=1024 possible compression techniques), whereas the techniques of the second group are identified, for example, by a 17 bit code (2¹⁷=131072 possible compressing techniques). Using such a configuration allows to incorporate the 50 to 100 most wide spread languages in the first group and to define about 8 to 10 preferred compressing techniques for each one of those languages. For both groups, it is possible to reserve a part of the entire code range (for example, the last 24 codes) for special functions. Such functions may include, for example, various predefined forms; control, regulation or communication protocols; audio, video, two- or three-dimensional graphical applications; appointment organizing applications; etc. When providing these latter functions, compression of the message elements of the second type is either omitted or said message elements are always compressed by using a predefined, fixed compressing technique independently of the language used by the user or of any other parameters.

If the compression techniques for the message elements of the second type are divided into two or more groups, the identifier of each group should also be associated with the output data set. As mentioned above, the compressed output data set generated from the message may be stored on a data carrier medium together with said aforementioned pieces of information or may be embedded in at least one standard data transmission message so as to be transmitted to one or more other device. According to the applied higher level protocols, further compression (or encoding) may even be performed, which is beyond the scope of the present invention. When the length of the compressed message to be transmitted is so large that the length of the output data set produced by means the method according to the invention exceeds the length of the pay-load field of the standard data transmission message to be used for transmitting the message, the compressed output data set is divided into several sections of suitable size and said sections are transmitted successively together with pieces of information identifying the respective sections, each of said sections being embedded in one of the multiple standard data transmission messages. In this case it is preferred that a header including at least the following fields are attached to the respective section of the compressed output data set in the standard data transmission messages:

- a special message starting bit sequence that identifies the message as compressed by the method according to the invention, - a field containing information identifying the compression technique selected for compressing the message elements of the second type (at least in the standard data transmission message carrying the first section),

- a field containing information identifying the particular section of the output data set.

In Figure 2, an example for the header used in the aforementioned preferred embodiment of the method according to the invention is illustrated. In this example, the message header includes the following fields:

- a special message starting bit sequence (14 bits),

- a header type indication field (2 bit) for indicating the section-based transmission and for identifying the groups of the compression techniques,

- a section-based transmission field (0 or 6 bits), wherein in case of the transmission of multiple sections, the total number of sections is represented by 3 bits, and the serial number of the particular section is represented by additional 3 bits,

- an identifier of the compression techniques for the message elements of the second type (10 or 17 bits),

- the length of the data field (11 bits).

The special message starting bit sequence may be any bit sequence that is likely not to occur in the text messages. Such a bit sequence may, for example, be a character code corresponding to the character pair "§fi" (which is a 14 bit code, for example, in the GSM 03.38 specification).

The two bit field identifying the header type may define the following headers, in a preferred embodiment of the method according to the invention:

When the output data set can be transmitted in one standard message, the field identifying the message sections has 0 bit, i.e. it is omitted from the header.

In a preferred embodiment of the method according to the invention, after finishing to edit the message, but just before the final compression of the message elements of the second type, in a further step of the method, a preliminary compression of the message elements of the second type stored in the temporary buffer may be carried out by using multiple different techniques selected from all of the available compression techniques, and then certain compression information is generated with respect to the message elements of the second type compressed by the various selected compression techniques and said information is presented to the user. The compression information may include, for example, the compression rate achieved by the various techniques, the number of free characters, or any other information supporting the user in making his decision. Thus, the user can select the final compression technique for the message elements of the second type from the available compression techniques, according the user's demands, to generate the output data set. In order to allow the user to make the selection faster, either a preset default compression technique or the compression technique providing the highest compression rate, for example, may be offered to the user. If the user does not accept the offered compression technique, he can select any other available technique.

The basic steps of a preferred embodiment of the method according to the invention are illustrated in the flow diagram in Figure 1. To carry out the method, at least one message element set including said message elements of the first type is predefined, in which a code is associated with each message element. Additionally, at least one compression technique for the message elements of the second type is also predefined.

In step S100 of the method, upon an initiation of the user, the message editing application is launched in the user device, thereby the user is provided with a tool to interactively generate the message, i.e. to add at least one message element of the first type and at least one message element of the second type to the message in any order. Accordingly, in step S102, it is examined whether the user wishes to add a predefined message element of the first type to the message. If the user starts the application for browsing in the message element set containing the message elements of the first type and designates a desired message element of the first type, then in step S104, the designated message element of the first type will be selected and in step S106 this message element will be added to the message. In step S108, the short code, i.e. the replacement code, associated with the selected message element of the first type is added to the temporary data set stored in the temporary buffer. Subsequently, in step S120, it is examined whether editing of the message is finished or the user still wishes to add any further message element to the message.

As mentioned before, one of the important and novel features of the method according to the invention is that by storing the replacement codes in the temporary data set, compression of the message is partly carried out as early as during generation (editing) of the message, and this operation also involves a user interaction.

If in step S102, it is established that instead of adding a predefined message element to the message, the user rather wishes to add an individual message element to the message, then in step S110, it will be examined whether a message element of the second type (text message element) is to be added. If so, then in step S112, a message element of the second type is added to the temporary data set stored in the temporary buffer in a character-based representation, and the method proceeds with step S120, in which it is examined whether editing of the message continues.

If the user does not wish to add either a message element of the first type or a message element of the second type to the message, then in step S114, it will be examined whether the user wishes to add a message element of a third type to the message. If this is not the case, then the method will proceed with the above mentioned step S 120, whereas if the user wishes to add a message element of a third type to the message (for example, by the user's selection of a menu item associated with such a function in the message editing application), then in step S116, said individual message element of the third type selected by the user (for example, a specific audio, video or other file read out, by the user, from the memory of the device in a compressed form) is also added to the temporary data set stored in the temporary buffer in an unchanged form.

The subsequent elements of the temporary data set, i.e. the replacement codes, the characters or character chains corresponding to the message elements of the second type and optionally, the message elements of the third type added in an unchanged form to the message, are separated in the temporary buffer by the insertion of suitable flag bits (groups of flag bits), for example. Alternatively, the various message elements may be differentiated, for example, through specific codes of the message elements, a special group of flag bits accommodated in the header, etc.

In step S120, it is examined whether editing of the message has already finished. Editing of the message cannot be regarded as finished until the message contains at least one message element the first type and at least a message element a second type. If in step S120, it is established that editing or generation of the message has finished (for example, the user selected a menu item in the message editing application corresponding to the termination of message editing, provided that the message contains at least one message element of the first type and at least one message element of the second type), then in step S122, the message elements of the second type stored in the temporary buffer will be temporarily compressed by multiple techniques selected from all available compression techniques, and in step S124, certain compression information with respect to the compressions carried out by means of the selected compression techniques is generated and presented to the user. Based on the presented compression information, the user can decide which compression technique is to be applied to the message elements of the second type and upon the user's decision, the compression technique to be applied is selected in step S 126, and then in step S128, the final compression of the message elements of the second type in the temporary data set is carried out using the selected compression technique.

Next, in step S130, a compressed output data set is produced from the replacement codes, the compressed message elements of the second type, and optionally, the unchanged message elements of the third type, each of said message elements being stored in the temporary buffer. Similarly to the temporary data set, the output data set may also contain special flag bits to separate the successive message elements, although any other suitable methods may also be applied to distinguish the message elements. If the user selected a compression technique for the message elements from multiple techniques, in step S132 at least a piece of information suitable for identifying the compression technique for the message elements of the second type is associated with the output data set, said piece of information being preferably accommodated in a header attached to the output data set. In case the message is to be transmitted to another device in a data transmission message (for example, within an SMS message) through a communication line, a special bit sequence is attached to the output data set, preferably at the beginning thereof, so as to indicate that the pay-load field of the data transmission message contains data compressed by means of the method according to the invention (and also additionally information associated with said data). At this step, the compression method terminates.

The present invention also relates to a computer program that contains instructions which, when being executed on a computer or other device having a processor, carry out any embodiment of the method according to the invention, including the aforementioned particular embodiments and also other embodiments of the invention not described herein but included within the scope of the invention.

The present invention further relates to a computer program product which is stored in a data storage medium readable by a computer or any other device having a processor, said computer program product comprising instructions which, when executed on a computer or other device having a processor, carry out any embodiment of the method according to the invention.

Obviously, decompression of a short message compressed by means of the method according to the invention is carried out in a reverse manner. Upon reading the compressed data and the associated pieces of information (for example, a header), it is recognized that the message contains data compressed by means of the method according to the invention. Next, the identifier of the compression technique used for the compression of the message elements of the second type are read, and if the compressed message was transmitted in multiple standard data transmission messages, the identifier of the compressed section transmitted in the particular message, as well as other pieces of information are also read from the associated information. Based on the aforementioned pieces of information, the decompression is carried out by using the predefined message element set(s) stored in the device carrying out the decompression, as well as the language specific code tables. Hence, the replacement codes are replaced with the corresponding message elements of the first type, the character codes are replaced with the corresponding language specific characters, whereas the message elements of the third type are left unchanged, and the thus obtained recovered input data set is stored or presented on the display of the device receiving the message or played by the speaker of the device or communicated to the user any other way.

Now the structure and the operation of compression system 200 adapted to carry out the method according to the invention will be described in detail with reference to Figure 3 in which a functional block diagram of a preferred embodiment of the system according to the invention is illustrated.

The compression system 200 comprises at least the following components:

- a message element set 210 including predefined message elements of the first type,

- a group of predefined compression techniques 220,

- means 230 for editing messages,

- means 240 for browsing message elements,

- means 250 for compressing data,

- means 260 for formatting messages.

In addition to the above listed components, preferred embodiments of the system according to the invention may comprise other optional components, from among which only the means 270 for sending and storing messages and the means 280 for presenting media can be seen in Figure 3 as represented by dashed lines.

Decompression of the messages compressed by means of the method according to the invention is preferably carried out by units corresponding to the above mentioned components and executing processes implementing the respective functions in a reverse manner, thus said units constitute a decompression system. Hereafter, for the sake of simplicity, only the units performing the compression will be described; the operation of the decompression units is regarded obvious for a skilled person on the basis of the operation of the compression units, and therefore the detailed description thereof is omitted. The message element set 210 containing the predefined message elements of the first type is stored in a data storage unit (memory) of the device using the compression system 200 according to the invention. In the preferred embodiments of the system according to the invention, the user is allowed to edit said message element set 210, in particular to edit or delete certain data therein (for example, groups of sentences having certain topics of represented in certain languages). In a preferred embodiment of the system, further message elements of the first type may be added to the message element set 210 stored in the device by loading down said message elements into the device from a central data base (not shown).

The predefined compression techniques 220 for the compression of the message elements of the second type are also stored in the data storage unit (memory) of the aforementioned user device. In a preferred embodiment of the system according to the invention, further compression techniques may be added or one or more technique may be removed from the group of said compression techniques 220.

The message editing means 230 is an interactive text editor application implemented in the user device, said text editor application being provided with special supplementary functions with respect to the conventional text editing applications so as to be adapted to carry out the compression method according to the invention. Beyond the function of conventionally entering a text message on a character basis, this application further allows to insert predefined message elements of the first type (for example complete sentences, portions of sentences, etc.) from the pre-stored message element set 210 into the message. Moreover, the message editing means 230 also allows to insert, for example, images, audio data or animations into the message. When a message is generated (or in case of a decompression system, when a received message is presented), the message editing means 230 presents the text message elements of the first type of the message in the language selected (preset) by the user. Obviously, the message editing means 230 is connected to data input and data output means (keyboard, display, etc.) of the user device.

In a preferred embodiment of the system according to the invention, when a message element of the first type is to be inserted, the message element browsing means 240 presents a hierarchical menu system, by means of which selected message elements (for example sentences, images, audio data, etc.) may be inserted into the message by navigating through predefined and optimized main categories and through subcategories within the main categories. In a preferred embodiment of the system according to the invention, the text message elements of the first type are offered in the form of text message elements stored in a default language preset in the user device, but preferably it is made possible for the user to select those text elements in another language, too. In the message element set 210 there may be cross-links, therefore a given message element may be reached even through more than one browsing path during the use of the message element browsing means 240.

The data compressing means 250 of the data compression system 200 according to the invention performs the replacement of the message elements of the first type with the corresponding replacement codes and also carries out the compression of the message elements of the second type by using the compression technique 220 selected by the user. The data compressing means 250 produces the compressed output data set 300 from the message in two steps separated in time, and makes the output data set ready to storing or transmitting. Accordingly, in the first step, during editing of the message, the replacement codes of the message elements of the first type are added to the temporary data set 255 stored in the temporary buffer, and then in the second step, after termination of editing of the message, the compressed message elements of the second type and optionally, the message elements of the third type in unchanged form are added to the temporary data set 255.

As mentioned above, it is preferred that multiple compression techniques for the compression of the message elements of the second type are pre-stored in the system according to the invention. In a preferred embodiment of the system, after termination of editing of a message, the data compressing means 250 performs a temporary compression of the message elements of the second type by using several selected techniques, and then generates certain compression information (for example, compression rate achieved by the individual methods, number of messages, number of free characters, etc.) with respect to the message elements of the second type compressed by means of the various compression techniques 220. This information is displayed (or read aloud) for the user on the display of the device preferably in a ranked order according to some aspect, upon which the user can select the most suitable compression technique 220 depending on the displayed compression information. It is also feasible that said data compressing means 250 automatically performs the final compression of the message elements of the second type according to a given compression techniques 220 preset by the user.

The message formatting means 260 has the function of altering the compressed output data set 300 into a format ready for storing (saving) or transmitting via a communication line. In case multiple compression techniques are available for the message elements of the second type, the message formatting means 260 associates with a compressed output data set at least the information identifying the compression technique 220 selected for the message elements of the second type. When the messages are to be transmitted, the message formatting means 260 may associate further information with the output data set. For example, it may attach a special bit sequence to the beginning of the output data set so as to indicate that a compression has been carried out by means of the method according to the invention, and optionally, it may also specify the size of the compressed data set in a corresponding descriptive field.

The compression system according to the invention may be combined, for example, with a message sending and storing means 270 that is used to store or to transmit the compressed output data set 300 and all information associated therewith (for example, a header). When transmitting the output data set and the associated information, those are embedded in the pay-load field of a data transmission message. The term "data transmission message" is to be meant as any kind of message transmitted in a wired or wireless communications system (for example GSM, Internet, intranet, etc.). In the field of the invention, such data transmission messages typically include SMS messages.

When sending a message, the message sending and storing means 270 saves the message automatically, and when the message is to be transmitted, said means forwards the message to the message sender subsystem of the device, for example to the SMS sender routine, in case of a mobile phone.

In a particularly preferred embodiment of the compression system according to the invention, the message sending and storing means 270 comprises a segmenting means (not shown is the drawings) that divides the output data set 300 into multiple sections of appropriate size. The message sending and storing means 270 sends the sections subsequently as embedded in multiple standard data transmission messages in a way that it also adds data suitable for identifying the respective section to the header belonging to particular section.

In the decompression system, a message receiving and storing means is used corresponding to the message sending and storing means 270, wherein said message receiving and storing means checks the header of the incoming message (by means of a resident client program) and if it recognizes a bit sequence identifying a message according to the invention, then it will store the message in a memory area reserved for the decompression system and will notify the user, who is receiving the message, in a pre-set manner. When the user message has been sent in the form of multiple sections within multiple subsequent standard data transmission messages, the message receiving and storing means is used to receive the messages in the correct sequence.

If necessary, the compression system 200 according to the invention may also be combined with a media presenting unit 280 that is adapted to read aloud the text message elements by synthesized voices or to play any other multimedia content transmitted in the message.

The compression system 200 according to the invention may further comprise a configurating means (not shown in the drawings) that allows the user to customize the operation of the entire system. This unit may be used, for example, to set the speaker volume or to mute it during reading aloud, to set the language actually selected or used as default by the compression system, to set a default list of the compression techniques, to set various compatibility modes, or to set other parameters relating to the appearance and the manipulation of the compression system, etc.).

A preferred embodiment of the system according to the invention further allows a weak encryption of the messages. This will have a great significant if the user's device gets to an unauthorized person or if the messages are accidentally transmitted to an undesired other device. Such encrypting methods that provide a rather simple and low-level supplementary protection are well known in the art, the implementation of such methods is a routine work for a skilled person and thus its detailed description is omitted here.

Beyond the transmission of short text messages, the compression method and system according to the invention may be advantageously and efficiently applied in several other fields including, inter alia, the following applications:

- remote control of household electronic devices (for example thermostat, alarm system, illumination, etc.);

- medical applications (for example automatic, mobile patient surveillance system for elderly or cardiopathic people that in case of emergency, sends a message to the mobile phone of an attending physician or to the mobile phone system of a medical center's dispatcher;

- remote voting, remote shopping, data transmission from a mobile phone, wherein the system comprises reserved command codes (replacement codes) that, instead of displaying or reading aloud a sentence in an arbitrary language, rather modify the color, the background or the position of a text to be displayed on the screen, and symbolize various check boxes, list boxes or building elements of a menu system object, and wherein certain symbols may also contain instructions relating to the utilization mode of the forms thus produced (for example, to what phone number and within which time frame a filled-in voting form can be returned); — organizing appointments by using mobile phones, even for groups with different native languages, wherein the system of the user initiating the appointment sends messages with possible appointment times to all concerned persons automatically, said messages being displayed preferably in the native language of the parties, an then the messages are returned on the basis of the diaries and the decisions of the addressees, and subsequently the messages are automatically evaluated and if necessary, transmitted repeatedly until the time and the place of the appointment are optimal for all of the parties;

- data files, video files, 2D and 3D images, animations may be downloaded to the user device by means of the system according to the invention.

Claims

1. A method for compressing short messages, in particular short text messages or short messages partly including text, wherein the message is composed of at least one message element of a first type and at least one message element of a second type, the number and the order of said message elements of the first type and said message elements of the second type being arbitrary, and wherein at least one message element set containing a plurality of message elements of the first type is predefined, each of said message elements of the first type being associated with a code, characterized by that the method further comprises the steps of

— during generation of the message, temporarily storing at least one code associated with said at least one selected message element of the first type (S108), and the at least one input message element of the second type (S112) in the order applied by the user, and

— after generation of the message, compressing the at least one temporarily stored message element of the second type according to a compression technique selected by the user (S128), thus producing a compressed output data set containing the codes of the message elements of the first and the second types.

2. The method according to claim 1 , wherein the method comprising the further steps of prompting the user, during generation of the message, to input at least one message element of a third type and adding said message element of the first type in an unchanged form to the compressed output data set (S116).

3. The method according to claim 1 or 2, wherein multiple compression techniques are predefined for the message elements of the second type and a method further comprising the step of associating a piece of information identifying the selected compression technique with the compressed output data set (S132).

4. The method according to any one of claims 1 to 3, wherein the method further comprising the step of storing the compressed output data set or transmitting the output data set as embedded in the pay-load field of at least one data transmission message.

5. The method according to claim 4, wherein if the size of the compressed output data set exceeds the length of the pay-load field of said data transmission message, the method further comprising the steps of

— dividing the output data set into sections of a predetermined size, and

— transmitting said sections subsequently as embedded in multiple data transmission messages and associating with each of the sections a piece of information identifying the respective section.

6. The method according to any one of claims 1 to 5, wherein said at least one message element set containing said message elements of the first type includes message elements of at least one type selected from the group of text, audio, still image, video image.

7. The method according to claim 3, wherein at compressing said message elements of the second type, the method further comprising the steps of

— temporarily compressing the message elements of the second type by using multiple techniques selected from the available compression techniques (S122),

— generating compression information with respect to the message elements of the second type temporarily compressed by means of the selected compression techniques and presenting said information to the user (S 124), and

— prompting the user to select a final compression technique for the final compression of the message elements of the second type on the basis of the presented compression information (S126).

8. A compression system for compressing short messages, in particular short text messages or short messages partly including text, the system comprising

— at least one message element set (210) containing a plurality of predetermined message elements of a first type, each of said message elements of the first type being associated with a code,

— at least one predetermined compression technique (220),

— message editing means (230) for generating said message from at least one message element of the first type selected by the user and at least one message element of the second type input by the user,

— message element browsing means (240) for selecting at least one message element of the first type from said at least one message element set (210) during editing of the message, and

— data compressing means (250) for replacing, during editing of the message, said message elements of the first type with their associated codes and for compressing, after editing of the message, said message elements of the second type by applying a compression technique (220) selected by the user, and thus for producing a compressed output data set (300).

9. The compression system according to claim 8, wherein the system comprises multiple compression techniques (220) and the system further comprises message formatting means (260) for associating, with the compressed output data set (300), at least a piece of information identifying the compression technique (220) selected for the message elements of the second type.

10. The compression system according to claim 8 or 9, wherein the system further comprises message sending and storing means for storing the compressed output data set (300) and optionally, any piece of information associated therewith, or for transmitting the output data set and optionally, said associated pieces of information as embedded in the pay-load field of said at least one data transmission message.

11. The compression system according to claim 10, wherein said message sending and storing means (270) comprises segmenting means for dividing the compressed output data set into multiple sections of a predetermined size and for associating, with each one of said sections, a piece of information identifying the respective section.

12. The compression system according to claim 11 , wherein said data compressing means (250) comprises pre-compressing means for temporarily compressing said message elements of the second type by using multiple different techniques selected by the user from all of the available compression techniques (220) and for generating compression information with respect to the message elements of the second type temporarily compressed by using said selected multiple compression techniques (220), and for presenting said compression information to the user.

13. The compression system according to any one of claims 8 to 12, wherein said at least one message element set containing said plurality of message elements of the first type contains message elements of at least one type selected from the group of text, audio, still image, video image.

14. The compression system according to any one of claims 8 to 13, wherein the system comprises multiple predefined message element sets and wherein the same replacement code is associated with the message elements having the same information content, but represented in different languages in the different message element sets.

15. A computer program for compressing short messages, in particular short text messages or short messages partly including text, characterized by containing instructions which, when executed on a computer or any other device having a processor, carry out the method according to any one of claims 1 to 7.

16. A computer program product stored in data storage medium readable by a computer or any other device having a processor, characterized by comprising instructions which, when executed on said computer or said other device having a processor, carry out the method according to any one of claims 1 to 7.