JPH0216623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a paging communication system for transmitting simple text to a wireless terminal and converting the text into a numerical code for display or audio output.

Background of the Invention Conventionally, when transmitting a simple sentence to a wireless terminal, the sentence is encoded character by character and transmitted. When characters such as kana, alphanumeric characters, and numbers are used, they are generally encoded using 7 to 8 bits.

Prior Art and Problems When using conventional methods to encode and transmit characters such as kana, alphanumeric characters, and numbers, the encoding method using 7 to 8 bits requires a transmission bit length of about 800 bits for a 100-character sentence, for example. need,
There were problems with the economical system configuration that hindered the effective use of radio frequencies.

Purpose of the Invention The present invention not only encodes character by character, but also encodes character by character.
It is possible to perform phrase-by-phrase and word-by-word encoding, thereby achieving extremely high efficiency encoding and making effective use of valuable radio frequencies.The drawings will be explained in detail below.

Embodiment of the Invention FIG. 1 shows an embodiment of the present invention, in which 1 is a terminal, 2 is a subscriber line exchange, 3 is a call communication exchange, 4 and 5 are modem trunks, 6 is a control unit, and 7 is a A memory, 8 a wireless base station, and 9 a wireless terminal.

To send a simple message from the terminal 1 to the wireless terminal 8, first dial the special number 1XY from the terminal 1, which will connect to the modem trunk 4 of the calling exchange 3 via the subscriber line exchange 2. When a response signal is sent from modem trunk 4 to terminal 1,
The modem built into the terminal 1 enters the transmitting state. The subscriber enters the other party's wireless terminal number and simple text from the keyboard of terminal 1 in numbers, alphanumeric characters,
When a pseudonym is entered, the modem of the terminal 1 sends out a predetermined code (for example, JIS information exchange 7-unit code, JIS C6220) and is received by the modem of the modem trunk 4. The terminal 1 may be a printer phone, a display phone, or a combination of a personal computer, an acoustic coupler, and a general telephone. Also applicable to the present invention is a system in which a general telephone is used as the terminal 1, input is made by voice, a voice recognition device is added in place of the modem trunk 4 of the call exchange 3, and sentences are directly identified by voice.

Sentences received by the modem trunk 4 are broken down into phrases, words, characters, numbers, and symbols by the control unit 5, and converted into numerical codes corresponding to each phrase, word, etc.

An example of the conversion algorithm is shown in FIG. The conversion algorithm is divided by a method called the longest match method, and a conversion dictionary that converts words and the like stored in the memory 7 into numerical codes is indexed. Now, when the sentence shown in FIG. 3 is received, first input up to the punctuation marks. In other words, enter (jitakuni) and index the dictionary. If the phrase (jitakuni) is found in the dictionary, the corresponding numerical code is extracted, but if it is not found, the phrase (jitakuni) is shortened by one letter and then indexed. (jitaku) is in the dictionary,
Extract the corresponding numeric code, for example (1234). Next, the remaining character (d) is indexed and the corresponding code, for example (75), is extracted. If there are no punctuation marks, first enter the maximum number of characters in the dictionary, shorten them one by one, and search for the largest word in the same way as above. In the example in Figure 3, (jitaku) (ni) (,) (denwa) (shitekudasai)
This is the case where the dictionary is listed and is converted into the numerical code shown in parentheses in Figure 3. This technique of breaking down sentences into words is known as ``bakigaki,'' and is used in word processors to convert kanji. Literature (e.g. Information Processing Society of Japan journals)
According to Vol. 20, NO4P337, Separation and Kana-Kanji Conversion of Solid Sentences (Makino, Kizawa), 97.2% separation is possible using a dictionary with 8226 words. If a phrase or word is expressed as a corresponding numerical code in binary code, there is a method in which everything is expressed as a binary code of a fixed length, for example, 2 bytes;
One possible method is to display frequently occurring words or phrases in 1 byte and other words or phrases in 2 bytes. Of course, the latter method has higher conversion efficiency. An example is shown in FIGS. 4a and 4b. Figure 4a is a 1-byte code (128 words), including numbers, kana, alphanumeric characters,
These are examples of frequently occurring words such as symbols and particles. The first bit of a 1-byte code is 0. Figure 4b is a 2-byte code (32768 words), which is a word other than the 1-byte code. The first bit of a 2-byte code is 1 to identify whether it is a 1-byte code or a 2-byte code. If you convert the sentence in Figure 3 with this code, ``(jitaku)'' is 1234 and 2 bytes,
(d) is 75 and is expressed in 1 byte. Third
The sentence in the figure can be expressed in 8 bytes in total, and in the general JIS code, the voiced mark is also expressed in 1 byte, so it takes 17 bytes. In this way, according to this method, it is possible to transmit data using approximately half the number of bits.

The control unit 6 in FIG. 1 transmits the code converted in this way to the modem trunk 5 along with the wireless terminal number.
is driven and transmitted to the wireless terminal 9 via the wireless base station 8.

When the wireless terminal 9 receives the converted code, the wireless terminal 9 indexes a code table that converts it into phrases, words, etc. from the numerical code built into the wireless terminal 9, converts it back to the original sentence, and sends it to the wireless terminal 9. displayed or sent as synthesized speech. The inverse conversion at the wireless terminal 9 can be easily realized using known techniques because it only has the function of uniquely indexing words or phrases using numerical codes.

When converting a phrase, word, etc. into a code using the control unit 6, multiple conversion methods are prepared, and the method to be used is selected according to the number of the wireless terminal 9 or an instruction from the terminal 1. The code is converted using the specified conversion method and sent to the wireless terminal 9, and the wireless terminal 9 either has a predetermined inverse conversion method or has multiple inverse conversion methods, and sends it to the wireless terminal 9. It is also possible to select in advance and obtain the original sentence by inversely converting the received code according to the conversion method. In this case, since the conversion method differs from terminal to terminal, there is an advantage that intentional eavesdropping is difficult due to erroneous reception by other terminals. Possible methods for converting multiple numbers include actually having a conversion dictionary for multiple numbers, or creating a new code by adding a fixed number to the code obtained with one conversion dictionary, and changing the constant number to be added. .

FIG. 5 shows a flowchart of processing operations on the sending side of the present invention, and FIG. 6 shows a flowchart of processing operations on the receiving side of the present invention. In the flowcharts of FIGS. 5 and 6, a word means a group of characters.

Effects of the Invention As explained above, when sending a sentence to a wireless terminal, by converting the code for each phrase or word,
It is possible to greatly reduce the transmission bit length and make effective use of valuable radio frequencies. Furthermore, by converting sentences into codes at the exchange, equipment can be centralized and an economical system can be realized. Furthermore, by providing a plurality of conversion methods and changing the conversion method for each terminal, it is possible to easily implement countermeasures against secret messages.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows a conversion algorithm for converting a sentence into a code, Fig. 3 shows an example of a sent sentence and an example of a conversion code, and Fig. 4 a and b show 1-byte codes of the conversion code. and 2-byte code example, 5th
6 are flowcharts of processing operations on the sending side and receiving side, respectively, of the present invention. 1... terminal, 2... subscriber line exchange, 3... call communication exchange, 4, 5... modem trunk, 6
...Control unit, 7...Memory, 8...Wireless base station,
9...Wireless terminal.

Claims (1)

[Claims] 1. In a paging communication system in which text is transmitted from a subscriber terminal or center to a wireless terminal via a communication network via a paging communication exchange and a radio base station, the paging communication exchange comprises: a control device; and a memory in which phrases, words, letters and numbers, or symbols and numeric codes are stored in correspondence; When the received sentence is received, the control device extracts a plurality of characters from the beginning of the received sentence, extracts the numerical code corresponding to the plurality of characters from the memory, and if there is a corresponding numerical code, extracts the next plurality of characters from the received sentence. Retrieve the characters and extract the corresponding numeric code, and if the corresponding numeric code is not in the memory, shorten the plurality of characters by one character and extract the corresponding numeric code. Repeat this process until all the received sentences correspond to the numeric code. Then, the paging communication exchange transmits the numerical code to the wireless terminal using a wireless line, and the wireless terminal converts the received numerical code into a corresponding phrase, word, character, number, or symbol, and A paging communication method characterized by display or audio output on a wireless terminal.