CH683052A5 - Transmitting long alphanumeric and pixel data over radio-pager POCSAG network - separating information, assigning data regarding separation to each part and transmitting, and combining parts at receiver using assigned data - Google Patents

Abstract

The graphics transmission method involves separating an information signal into a number of parts and assigning additional information to each part regarding the separation. Each signal part and additional data does not exceed a given length, and all parts with associated data are transmitted independently. The transmitted signals are received where the information signal parts are combined on the basis of the additional data. USE/ADVANTAGE - For transmitting large amt. of information, esp. image by radio over network with limited reliable transmission of data messages e.g. over paging network. Transmits both alphanumeric and image pixel information, e.g. Arabic, Japanese and Russian characters.

Description

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description

The invention relates to a method for transmitting long messages to individual paging receivers in a paging network, in particular a network with a limited permissible message length. The invention further relates to a radio paging receiver for carrying out the method and a radio paging transmitter. Paging networks, also referred to as paging networks, can be constructed as local or nationwide systems that transmit digital signals to small, portable paging receivers (pagers) via radio stations or so-called base stations to expand the telephone network. Digitally coded alphanumeric messages, such as the name of a person to be called by the carrier and their telephone number, or any other messages can be transmitted to the recipient. The devices serving as call receivers are designed in such a way that they receive the radio signals of the base stations reliably at a high transmission speed and recognize the message transmitted therein, and can display them on a display device. With newer paging receivers, a display field with a large number (e.g. 32 x 100) pixels is provided for displaying the message, which allows the display of several lines of text. The display fields are usually designed as LCD elements.

The alphanumeric messages are transmitted in the standardized POCSAG format (CCIR recommendation 584, 1982), using ISO 7-bit letter coding for the Latin letters (ISO standard 646). Each letter of the message is assigned a 7-bit binary word according to this coding table on the transmitter side. On the receiver side, the received message is decoded and fed to a character set memory (ROM), in which this table is also stored. With the help of this memory, the associated letter is assigned to each 7-bit word. The characters of the message determined in this way are displayed as a string of characters in a 5x7 dot matrix display.

If special characters are to be shown that are not provided in the table, the table must be expanded. This requires the programming of a ROM module with a corresponding table. This is also necessary for non-Latin character sets (e.g. Arabic, Japanese, Russian characters), whereby very large tables or ROM memory capacities are necessary for such character sets. The programming of such ROM memories is time-consuming and expensive.

On the one hand, it is therefore desirable to be able to transmit messages as their graphic image, so that no character set memory is required for, for example, Chinese characters. These are recorded as an image pixel by pixel, transmitted pixel by pixel and displayed on the point matrix display of the receiver made up of pixels. Any image can be transferred in this way.

In particular in the case of the described transmission of pixels, but also in general in the transmission of long alphanumeric messages, that is to say using the character set memory, the problem arises that long messages can overload a paging network. Furthermore, the likelihood of long messages being disturbed increases, which can impair their correct reception or playback. It is therefore the case that there is usually a limit on the maximum permissible message length in the paging network.

It is an object of the invention to remedy this situation and to enable long messages to be transmitted to the paging receiver. On the one hand for long alphanumeric messages, but on the other hand especially for the pixel-by-pixel transmission of messages.

The object is achieved in a method of the type mentioned at the outset in that the long message is broken down into at least two parts and each part is provided with an addition which contains information about the division of the excessively long message, the part and addition not each having a predetermined message length exceed that the parts with their respective additions are transmitted on the paging network as independent individual messages, and that the independent individual messages are composed in each case in the paging receivers addressed by the transmission on the basis of the additional information for the overlong message.

The addition, which can be brought into a format which is acceptable to all encoders of paging centers, allows the long message in the pager to be composed of the individual messages which do not necessarily arrive in the correct order at the pager. In this way, long messages that are longer than the normally permitted messages can be divided into individual messages of shorter, permitted length. In this way, the paging network is not blocked, but used efficiently. If parts of the long message are faulty, they can be replaced when they are sent again. Parts of a long message can also be changed to form a new long message; only the changed part has to be re-transmitted. The probability of correctly receiving a plurality of short messages may be higher than that of correctly receiving a long message.

Preferred embodiments of the method are defined in claims 2 to 12.

A preferred area of application is in particular the transmission of characters and images as a sequence of pixels, with large amounts of data being generated, which is equivalent to long messages.

By coding the graphic image of the message and the pixel-wise transmission and

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the corresponding decoding and representation on the display panel, the need for a coding / decoding table or for the character set ROM is eliminated. Any characters can be transferred pixel by pixel. Images that use the entire display field can also be transmitted.

Preferably, however, the transmission is optionally switchable using the previous character set table or the graphic transmission. On the one hand, this allows the fast transfer of characters already recorded in the character set and enables the switch to graphic transmission for the special characters not recorded in the table. Instead of this switchover within a message, it can also be provided that it is only possible to switch between different messages, so that one message is sent as exclusively character-coded, the next message as exclusively graphically coded.

Claims 13 and 16 define a portable radio paging receiver and a radio paging transmitter for carrying out the method.

In particular, the radio pager is preferably provided with a character set memory and a switching arrangement, by means of which the message can optionally be switched, with permanently programmed characters from the memory or with graphically transmitted characters.

Exemplary embodiments of the invention are explained below with reference to the drawings. It shows

Fig. 1 shows schematically the structure of a paging network;

2 schematically shows the structure of a radio paging receiver according to the prior art;

3 schematically shows the structure of a radio paging receiver according to a first embodiment of the invention;

4 shows the representation of a graphically transmitted message;

5 schematically shows the structure of a pager according to a further exemplary embodiment; and

6 shows the representation of a graphically transmitted letter.

1, a paging network is composed of a paging transmitter 13 to 18 and a plurality of portable paging receivers 19. In a paging terminal 14, which is the link between the public telephone network 13 and the paging system, the subscriber data is managed and the incoming calls in serial data streams suitable for the paging system, e.g. implemented in the so-called POCSAG format.

A network control unit (paging network unit) 15 is connected to the paging center and collects a certain number of calls in each case in a data packet. Each data packet is encoded accordingly and made available for further transmission. The calls are temporarily stored for transmission. The network control unit is also responsible for the synchronous transmission of the radio calls. For this purpose, it stamps each paging with a time stamp that defines the time of its transmission.

A plurality of locally distributed transmitter group control units (transmitters group controllers) 16 are connected to the network control unit (via telephone lines). These transmitter group control units distribute the data packets that they receive from the network control unit to the actual paging transmitter or base stations.

The base stations (base stations) 17, of which several are connected to a transmitter group control unit (via telephone line), represent the end of the line-bound or the starting point for the radio transmission of the calls. The calls are transmitted from the base stations to the Receiver forwarded.

The call receivers (paging receivers) 19 are carried by the subscribers and receive the radio calls addressed to them. 2, which shows a highly schematic diagram of a call receiver according to the prior art, a receiver circuit 1 for receiving the radio calls on one or more specific frequencies is provided in this. The digital bit sequences received are output to a data processing circuit or decoder circuit 2. This decoder circuit first determines whether the transmitted, standardized data stream contains in its address part an address which is assigned to the specific pager. There are usually several, e.g. four, assigned addresses under which it can be addressed separately and under which separately cacheable messages can be sent to the call recipient. If the address preceding the message does not correspond to any address of this call recipient, the message is ignored. If the address corresponds to one of the call recipient addresses, the associated message is stored in the corresponding buffer 30-33. A saved message is displayed on display field 3. This is e.g. formed by an LCD display element with 32 x 100 display elements. According to the state of the art, four lines of text are shown on this display element. The message consists of a series of 7-bit binary words, each of which corresponds to a letter or other character. These binary words are applied by the decoder circuit 2 as an address to a character set memory (ROM) 4. This memory outputs the dot matrix representation (e.g. 5x7 dot matrix representation) of the corresponding letter to the display field 3 as data. Via a control line 6, the decoder circuit 2 effects the corresponding stringing together of the letters in the four lines of the display field.

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Only characters (letters, numbers, punctuation marks, special characters) can be displayed, whose assignment 7-bit code to 5 x 7 - dot matrix representation was previously saved in the ROM.

In the following, the method for the transmission of long messages will first be explained using an example. A long message is a message that is longer than a message that can be transmitted by the network operator in a transmission cycle. The network operator (system operator) limits the maximum length of messages that can be entered into the network for several reasons, in particular in order not to reduce the quality of the paging service for other users and to avoid the reliability problems of the reception when sending long messages.

When solving the problem, in addition to the maximum length of the message, it should be noted that the amount of alphanumeric characters allowed in the system is also limited by the network operator. However, special codes must be entered into the system in such a way that they are not rejected as inadmissible. It should also be noted that the order in which messages are received by the pagers is not known when messages are entered into the system.

In order to send a long message, the invention therefore divides this long message into individual messages which are acceptable to the system and which are sent by the system as completely independent individual messages to the pager (s) intended for this. In the respective pager e.g. specified a subaddress as an address for receiving long messages. To enable the individual messages arriving at the pager to be put together in random order to form the long message, each part of the message is provided with an addition; The message part and addition form the individual message to be transmitted.

Preferably, three characters of 7 bits each, ie 21 bits, are used as an addition to each message part. The addition is added to the message part e.g. prepended as head.

In order for normal paging networks to accept this addition, the most significant bit (MSB) is selected as 1. In the following illustration, the lowest significant bit (LSB) is given first. The addition is preferably structured as follows:

X1, X2, X3, X4, X5, X6, 1, Y1, Y2, Y3, Y4, Y5, Y6, 1, Z1, Z2, Z3, Z4, Z5, Z6, 1;

where the bits are defined as follows:

X1 and X2 0 for the present embodiment; other combinations can be selected for special functions.

X3, X4, X5 Define a run number 0-7.X3 is the LSB

X6, Y1, Y2, Y3 Define the number of blocks of 20 characters each in the respective

Individual message can be transmitted. X6 is the LSB.

Y4, Y5, Y6, Z1, Z2, Z3, Z4, Z5, Z6 Define the number of blocks of 20 characters each in the respective

Individual message and the following individual messages belonging to the long message are transmitted. Numbers of 1-512 are used. Y4 is the LSB.

Transmissions are preferably carried out only in whole blocks of 20 characters. Spaces are used to fill up a block if necessary. Long messages of up to 10 240 characters can be transmitted in this way.

For example, the following message is sent to a pager or a group of pagers:

After the failure of the orange harvest in Florida, it is expected that the price of January orange juice will raise by 25%

This message is 124 characters long. Such a message has not yet been able to be transmitted in the Swiss paging network, since the maximum permissible message length is 80 characters.

The message is now broken down into two parts:

Part a Afler the failure of the orange harvest in Florida, it is expected that the p Part b rice of January orange juice will raise by 25%

Part a consists of 77 characters and is now supplemented with the addition consisting of 3 characters (7 bits each). The individual message, which consists of part and addition (header), comprises 80 characters. If the individual message is the sixth message to the pager, it receives the sequence number 6 or binary 011 (LSB as the first bit). Part a consists of 80 characters including the header, and therefore the number of blocks of 20 characters transmitted in the individual message is 4, binary 0010.

Part b consists of 47 characters, ie three blocks of 20 characters each, including spaces for filling; Therefore, in addition to part a, the number of transmitted blocks plus the following blocks is given as 4 + 3 = 7, binary 111,000,000.

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The head for part a is as follows:

X1 X2 X3 X4 X5 X6 1 Y1 Y2 Y3 Y4 Y5 Y6 1 Z1 Z2 Z3 Z4 Z5 Z6 1 000110101011110000001 0 6 4 7

X z ü

in Switzerland, this 3 x 7-bit string is transmitted as X z ü as already shown above. For part b, consisting of 47 characters, 3 blocks of 20 characters are used. This individual message is not followed by any further individual message belonging to the overall message. The serial number for the long message is 6. The header for part b is therefore as follows:

X1 X2 X3 X4 X5 X6 1 Y1 Y2 Y3 Y4 Y5 Y6 1 Z1 Z2 Z3 Z4 Z5 Z6 1 000111110011010000001 0 6 3 3

x ç ü

In Switzerland, as indicated above, this head is transmitted as x ç ü.

The individual messages A, B transmitted completely independently of one another are therefore:

A XzüAfter the failure of the orange harvest in Florida, it is expected that the p B xgürice of January orange juice will raise by 25%

Even if the pager receives message B before message A, it can see from the mind that A and B are parts of the same long message and that A belongs to B. Repetitions of the individual messages A and / or B also pose no problems for the pager, since the individual messages can always be logically correctly assigned to the overall message.

Fig. 3 shows an embodiment of a paging receiver. The receiver circuit is again designated by 1. 40 denotes a data processing circuit or decoder circuit. The decoder circuit is now designed in such a way that it decodes the first three characters of each individual message directed to the predetermined subaddress accordingly, and accordingly assigns or stores and displays the individual messages to one another. In this example, the decoder circuit 40 is connected directly to the display panel 3 via the data line 35. A preferred aspect of the invention will now be explained, according to which messages are transmitted pixel by pixel, which results in large amounts of data or very long messages which, according to the invention, are separated into individual messages. A message, e.g. the image shown in FIG. 4 is transmitted pixel by pixel according to the invention. On the transmitter side, the image of the message, be it a plain text or, as shown, an image and text message, is broken down into a number of pixels which corresponds to the number of pixels of the display field 3 of the call receiver. The binary value 0 or 1 is assigned to each pixel, depending on the state OFF or ON (LCD element) or LIGHT or DARK (optical impression) of the respective pixel. The message thus broken down in the pixel or in bits is addressed to a radio paging receiver and transmitted bit by bit as a large number of 80 characters long individual messages. The pager has e.g. the display field 3 shown in FIG. 4 with 32 x 100 pixels. The image is preferably built up line by line at the transmitting and receiving sides, one line being 2 times four pixels high. These 2 x four pixels can each be transmitted as 2 x 4-bit binary words; 100 2 x 4-bit binary words are thus transmitted for one line. In order to maintain full compatibility with the previous data formats in a paging network, the individual 2 x 4-bit words are preferably each supplemented to 2 x 7-bit words, e.g. the 4-bit word 1111 to 0001111. The 16 possible 4-bit words from 0000 to 1111 thus represent the characters 0 to 9, space, U, [,] and «spare» in the 7-bit code. Starting in the first The line in the upper left corner of the illustration in FIG. 4 is the transmitted binary sequence, for the sake of simplicity without addition to 7 bits, 0000 0000/0001 0010/1000 etc. until the first line has been transmitted

(the activated pixels are only shown as a box in FIG. 4). Then the second line with the binary words 0000 0010/0010 0100/0000 1000 / .... etc. is transmitted. Lines 3 to 4 follow in the same way. When the message transmitted in this way is displayed in the radio paging receiver, the decoder circuit 40 via the control line 6 to the display field 3 ensures that the line is switched within and line by line. Via the 4-bit data line 35

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relevant bits of the 7-bit binary words are applied to the display field in order to activate the corresponding pixels. In this way, it is possible to send any pictures and texts to a pager. However, it can be seen that more information must be transmitted in this way than in the transmission according to the prior art. There, a 7-bit word is sufficient to transmit a letter; in the described method, the letter must be transmitted pixel by pixel with a large number of 7-bit words. This does not pose any problems in itself with lightly loaded paging networks. It is therefore quite conceivable to use a radio network that is not very busy, i.e. to operate one with few participants, in which only complexly encodable characters are used (e.g. Chinese, Thai or Cyrillic characters), based on this pixel-by-pixel transmission. In the case of heavily used networks, the long transmission times required can be problematic.

Preferably, both types of transmission are therefore optionally switchable. Alphanumeric texts that only use characters from a character set memory in which a basic set of characters are encoded are transmitted in a known manner in encoded form. If special characters are to be displayed that are not contained in the character set memory, then the transmission described by pixel is switched over and transmitted point by point.

Fig. 5 shows schematically a radio paging receiver 19 with a corresponding structure. A decoder circuit 41 with buffers is connected to the receiver circuit 1. On the one hand, the decoder circuit has a control output for line control of the display panel 3, which is connected to the display panel via the control line 6. On the other hand, a control output and a control line 7 are provided for a switching arrangement 43 which is arranged in the data line. In the one position of the switching arrangement, the received bit words are sent as addresses to the character set memory 4. This gives the predetermined, stored character representations via line 34 to the display field. In the other position of the switching arrangement, the bit words go directly to the display field to activate individual picture points.

There are two options for switching between the transmission types. On the one hand, the type of transmission can be permanently assigned to an address of the pager. For example, two of the four addresses of the pager are reserved for pixel-by-pixel transmission. If the pager is addressed at one of these two addresses, the switching arrangement 43 and the display field 3 are controlled accordingly by the decoder circuit. The character set memory 4 remains unused. If the pager is addressed at one of the other two addresses, the switching arrangement is switched over in such a way that the received bit words reach the character set memory 4 and its output signals control the display field 3 via line 34. Correspondingly, the line connection of the display field 3 is also influenced via the control line 6, so that in one case the consecutive 7-bit words control columns of the display field that are adjacent to each other in a line, 2 by four pixels high, in the other case in each case in a line adjacent 5x7 dot matrix fields.

The other way of switching between the transmission and display types is to switch within a message. This allows optimal use of the advantages of both types of transmission. The character set memory is used for standard characters (e.g. the usual Latin letters and numbers) within the message.

However, any special characters can now be present in the message which have no equivalent in the character set memory. If such a character occurs, the system switches to pixel-by-pixel transmission, the decoder circuit 41 controls the switching arrangement in order to give the relevant bits of the 7-bit words to the display field, and the special character is constructed from individual pixels. Then the switch back to character set transfer takes place. The switch from character set transmission to pixel transmission can be triggered by a predetermined 7-bit binary word, since not all possible 7-bit words are required for the character set transmission. If the predetermined 7-bit word appears, which does not represent a representable character, this is recognized by the decoder circuit as a switchover signal for pixel-by-pixel transmission. Since all possible 2 x 4-bit words are required for this type of transmission, the switch back to character set transmission cannot be triggered by a 4-bit word. The switch back is therefore carried out in such a way that it takes place automatically after a predetermined number of 2 x 4-bit words (e.g. after ten 2 x 4-bit words) by the decoder circuit.

Since there are several free 7-bit words in the code, several of these words can be used as switching words, with each 7-bit switching word corresponding to a different number of 2 x 4-bit words until switching back. This enables a flexible switching time depending on the complexity of the character to be displayed pixel by pixel. Fig. 6 shows the pixel structure of the character ü. The corresponding 4-bit words are 0111 1110/1000 0010/0000 0010/1000 0010/0111 1110. As 7-bit words, the representation of the ü is transmitted pixel by pixel as a string> 7 1 404 1 4> 7.

At most, additional information can be transmitted in the three preceding bits, e.g. Color information in the case of a multicolor display element 3. When transferring graphics, such as 4, a large number of individual representations can also be transmitted if the pager is equipped with sufficient memory space. If these representations are then quickly read from the memories one after the other and displayed on the display panel, a moving image can be displayed.

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Claims (17)

Claims 1. A method for transmitting long messages to individual paging receivers in a paging network, in particular a network with a limited permissible message length, characterized in that the long message is broken down into at least two parts and each part is provided with an addition which provides information about the division of the excess Contains message, the part and addition not exceeding a predetermined message length in each case, that the parts with their respective additions are transmitted on the paging network as individual messages which are independent of one another, and that in the paging recipients addressed by the transmission, the independent individual messages are based on the additional information relating to the excessively long message be put together. 2. The method according to claim 1, characterized in that the addition is designed as a head preceding the part. 3. The method according to claim 1 or 2, characterized in that the addition contains information about the length of each part and the message length and a sequence number. 4. The method according to any one of claims 1 to 3, characterized in that the addition has a length which corresponds to three characters. 5. The method according to any one of claims 3 or 4, characterized in that the addition contains a sequence number from 0 to 7. 6. The method according to any one of claims 3 to 5, characterized in that the information about the message length contains a first section that indicates the number of blocks of twenty characters that are transmitted with the single message, and a second section that the number Blocks of twenty characters each, which are transmitted with the transmitted individual message and the following 5 individual messages. 7. The method according to any one of claims 1 to 6, characterized in that a graphic image of the message is transmitted pixel by pixel. 8. The method according to claim 7 for transmitting digitally coded messages in a paging network comprising at least one coding device (14, 15), at least one transmitter device (16, 17, 18) connected thereto and a plurality of portable paging receivers (19), each with a receiver circuit ( 1), a decoder circuit (40, 41) and a display field (3) with a plurality of pixels for reproducing the message, characterized in that the graphic image of at least part of the message is broken down into a number of pixels on the coding side and the individual pixels each Binary value 0 or 1 is assigned so that a binary sequence is formed from the binary values and these are transmitted as a plurality of individual messages to the pager (19) intended for receiving the message, and that on the decoding side the individual messages are combined to form the message and at least one pixel for each bit assigned to the display panel (3) and di it is activated or deactivated according to the binary value in order to display a graphic image of the message on the display field. 9. The method according to claim 8, characterized in that the message is optionally switchable as a bit sequence corresponding to the graphic image or as a character sequence coded bit sequence according to a predetermined character set assignment. 10. The method according to claim 9, characterized in that the radio pager addressed is given the command to switch the decoding between predetermined character set assignment and graphic mapping by at least one predetermined binary word within the character set-coded bit sequence, and that after a predetermined number is coded as a graphic image Bits are switched back to decoding according to the character set assignment. 11. The method according to claim 10, characterized in that a plurality of predetermined switchover binary words are provided, each being assigned a different preselected number of graphically coded bits. 12. The method according to claim 9, characterized in that the addressed radio pager is given the command to switch the decoding between character set mapping and graphic mapping with the address sent before the actual message. 13. Portable radio pager for performing the method according to one of claims 1-12, characterized by a decoder for detecting the addition, a memory for storing a plurality of individual messages and a circuit for calling the individual messages in the correct order to display the entire message. 14. Portable radio paging receiver according to claim 13, with a receiver circuit (1), a decoder circuit (40) connected thereto and a display field (3) with a plurality of pixels, characterized in that the decoder circuit (40) for controlling each pixel of the display field ( 3) is configured depending on the binary value of a corresponding bit of the received bit sequence. 15. A portable radio paging receiver according to claim 14, characterized in that a character set memory (4) and a switching arrangement which can be controlled by the decoder circuit (43) are provided, the switching arrangement (43) having a first switching state, in each of which a received binary word is sent to the character set memory (4) can be created, whereby a character assigned to the binary word can be given to the display field (3), and a second switching state in which the 7 5 10th 15 20th 25th 30th 35 40 45 50 55 60 CH 683 052 A5 received binary words can be output to the display field bypassing the character set memory, as a result of which individual pixels can be represented in accordance with corresponding individual bits of the binary word. 16. Paging transmitter for carrying out the method according to one of claims 1-12, characterized in that a message to be sent can be broken down into a predetermined number of pixels, the individual pixels being assigned a binary value of 0 or 1, and that one of the binary values the pager can be formed by the sendable bit sequence. 17. Paging transmitter device according to claim 16 for carrying out the method according to claims 2 to 5, characterized in that the message can be sent either as a coded graphic image of the message or as a sequence of characters coded according to a character set table. 8th