JPH11196037A - Digital data communication system and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select a suitable error correction method according to the type and significant of data and to perform effective communication of data by suitably selecting plural error correction means for conducting communication between slave units. SOLUTION: A data communication frame consists of a data part 102a, which performs the communication between the slave units other than the voices, an error check part 102b and a control information part 102c. The length of the part 102b can be changed, based on a high speed-priority or an error correction-priority mode, and the length of the part 102a is also changed according to the length of the part 102b. Higher priority is given to the error correction mode compared with a high speed mode for the communication of the text data. Thereby, the communication is performed via a correction-priority frame 302. Meanwhile, the higher priority is given to the high speed mode for the communication of the moving image data. Thus, a high speed-priority frame 301 is used. In other words, the importance is attached to a high speed mode for the communication of dynamic images and then to an error correction mode for the communication of the text data respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a communication system,
The present invention relates to a digital data communication system and a method for changing settings of communication conditions on a transmission side and a reception side according to the data type.

[0002]

2. Description of the Related Art Conventionally, for example, a PHS (Personal H
In the communication between slave units using the andyphone System), the signal to be transmitted wirelessly is usually a voice call signal, and even if a certain amount of noise or the like occurs, it does not cause a serious problem. No means was provided.

[0003]

[Problems to be solved by the invention] However, in the future,
In the communication between slave units as described above, not only voice,
It is expected that various types of image data and text data will be transmitted. Due to the nature of the data to be transmitted, for example, when transmitting important document information, the occurrence of noise or the like as in the above-described voice call may not be acceptable, and it is necessary to perform a certain error correction. Become.

However, if uniform error correction is performed in various types of data transmission (voice, text, still image, moving image, etc.), depending on the type of data, error correction which can be regarded as redundant may be performed, and high-speed data transmission may be performed. Communication has been hindered, or the effective use of wireless resources has been hindered, and further, there has been a problem that communication costs (such as battery consumption) are disadvantageous.

[0005] For example, when transmitting moving image data, it is necessary to continuously transmit images at high speed. Since high-speed communication is performed, it is difficult to perform redundant error correction. On the other hand, when transmitting a still image, it is desired to transmit a clear image with as few errors as possible, although not so high-speed communication is required.

It is an object of the present invention to provide a data communication apparatus and method capable of selecting an appropriate error correction method according to the type or importance of data to be communicated in terminal communication.

[0007]

In order to achieve the above object, a digital data communication system according to the present invention provides a digital data communication system in which a transmitting terminal and a receiving terminal communicate using a wireless communication transmission path. Wherein the transmitting terminal has two or more data error correcting means, and a selecting means for selecting the error correcting means, and the receiving terminal has two or more data error correcting means, By having a selecting means for selecting a correcting means, the error correcting means can be changed according to the type of data to be transmitted and received or the importance of the data.

More specifically, in a digital data communication apparatus, an error correction means that emphasizes error correction over high speed data communication and a high speed data communication over error correction according to the type of data transmitted and received. The data communication is performed by appropriately changing the error correction means.

[0009] Thus, by changing the error correction according to the type of data such as text data, still image, moving image, etc. as well as audio, it is possible to omit error correction which can be considered redundant depending on the type of data, and Improvements can be achieved in terms of data communication, effective use of wireless resources, and communication costs (battery consumption, etc.).

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a personal handyphone system (PH) will be described as an embodiment of the present invention.
A service in the case of performing communication between slave units in a wireless communication system using S) as a wireless communication medium will be described as an example.

FIG. 1 is a schematic diagram showing a configuration of a wireless communication system using a PHS as a medium according to an embodiment of the present invention.

This system comprises a private branch exchange 1100, radio base stations 1111a to 1111c, a PHS telephone 11
10a to 1110c. Each of the wireless base stations 1111a to 1111c has an area 1112a.
~ 1112c.

The private branch exchange 1100 is connected to the exchange 110
0 and a public line or PBX 1140, an external line I / F unit 1101 and a radio base station 1111x (x is a
To c) and the exchange 1100, a line control unit 1102 for controlling the connection state of the line, a control unit 1104 for controlling the operation of the exchange 1100, and various types. RAM 1 for storing data
105 and voice mailbox 11 for storing voice information
06.

FIG. 2 shows a wireless terminal (PH) according to this embodiment.
It is a block diagram which shows the structure of S telephone 1110x).

The radio terminal 1200 includes an RF unit 1201 for transmitting and receiving radio signals via an antenna, a modem (modem) unit 1202 for modulating transmission data and demodulating received data, and disassembling / assembling a frame. TDMA
A channel codec unit 1203 for performing processing, error correction processing, scrambling processing, and confidential processing of audio data;
An ADPCM unit 1204 that performs compression encoding processing and decompression decoding processing of audio data.

A digital processing unit (IC) 1211 for processing digital data; a control unit 1205 for controlling each unit; a RAM 1206 for storing various data;
An input unit 1207 for inputting a dial or the like, and an LED / L
A display unit 1208 such as a CD, a transmitter 1209, and a receiver 1210 are provided.

The control unit 1205 has a function of performing an application process for executing digital communication, and determines whether to perform high-speed communication or error correction-oriented communication during data communication described later. The controller 1205 determines the channel codec 1 based on the determination.
In step 203, a process of changing the frame to be assembled is performed.

FIG. 3 is an explanatory diagram showing the relationship between slots and the structure of a frame when data communication is performed in a wireless communication system using a PHS as a medium according to this embodiment.

The control slot (SCCH) 100 is used for performing call / response / synchronization when performing communication between slave units. The control slot 100 is composed of data of a start symbol SS, a preamble PR, a uniword (synchronization word) UW32, a channel type CI, and an error check CRC.

A physical slot (TCH) 101
Is used to transmit and receive data (usually voice) when a communication state is established when performing communication between slave units. The physical slot 101 includes a start symbol SS, a preamble PR, a uniword (sync word) U
W16, channel type CI, always associated control channel SA
(SACCH), information element I, and error check CRC data.

The data communication frame 102 is constituted by the information element I and is used when performing communication other than voice in communication between slave units. The data communication frame 102 includes a data section 102a, an error check section 102b, and another control information section 102 for performing non-voice communication in communication between slave units, which is a feature of the present invention.
c. The length of the error check unit 102b can be changed, for example, between high-speed emphasis and error correction emphasis described later, and the length of the data unit 102a is changed accordingly.

The control information section 102c includes a frame type FI, a frame number FFI, a requested frame number FB
I, a continuation frame identifier that specifies the continuation relationship of the user data divided into frames, a data length indicating the significant information length of the user data area, and D used for modulo identification
It is composed of S data.

FIG. 4 shows in detail the information section (I) of the control slot 100 in the case of performing communication between slave units in the present embodiment.

The data type 200 is an area for selecting a data type which is a feature of the present invention, and can specify voice / text / moving image / other as a data type. In other words, when the receiving handset (hereinafter referred to as PS) receives the calling service from the calling PS, the data type 2
With reference to the area No. 00, the communication to be performed can recognize any of the above-mentioned voice / text / moving image / other.

FIG. 5 is an explanatory diagram showing a frame configuration when data communication is performed between slave units in the present embodiment.

First, reference numeral 300 denotes the configuration of the data communication frame. As described with reference to FIG.
a, an error check unit 102b, and a control information unit 102
c (DS is omitted). Reference numeral 301 denotes a configuration in the case of a moving image data communication frame, 301a denotes an error check unit, and 301b denotes a data unit. For a moving image, real-time high speed is required, so the error check unit 301a uses the CRC 16 that finds only an error.

Reference numeral 302 denotes the configuration of a data communication frame for performing text data communication.
a indicates an error check unit, and 302b indicates a data unit. For text data, from the viewpoint of emphasizing error correction, a Reed-Solomon code including error correction is used as an error method, and an error correction method that increases the validity of the data is selected.

FIG. 6 is a flowchart showing the operation of the receiving side PS when performing communication between child units in this embodiment.

When the receiving PS receives the SCCH call addressed to itself (S400), the receiving PS determines whether the data type shown in FIG. 4 is voice or not (S401) and the normal voice sequence (S402) and bearer. Sequence (S403)
Communication (RCR-STD)
28).

FIG. 7 is a sequence diagram in the case of performing voice communication in communication between child units in the present embodiment.

When a call is originated, the originating PS uses voice to communicate from now (data type = 0).
0) is transmitted to the receiving side PS together with the call information (S)
500). When receiving the call information, the receiving side PS confirms that the data type is voice, and the RCR-STD 28
Is performed with the originating PS to perform communication (S501). At this time, the data communication frame 102 shown in FIG. 3 is not configured.

FIG. 8 is a flowchart showing an operation of selecting a correction method when data communication is performed between slave units in the present embodiment.

In this example, when text data is communicated, the communication which emphasizes correction rather than high speed is performed.
In the case where communication is performed using a communication frame that emphasizes correction as shown in FIG. 02 and video data is communicated, communication that emphasizes high speed is performed. Therefore, communication is performed using a communication frame that emphasizes high speed as shown in 301 in FIG. Do.

That is, in the communication of moving images, it is necessary to continuously transmit image data in real time, so high speed is emphasized, and in the communication of text data, correction is emphasized in order to ensure data accuracy. Perform communication. In the communication of a still image, the communication is performed using the communication frame 302 that emphasizes correction, as in the case of the text data.

In S401 of FIG. 6 described above, if it is determined that the communication is data communication, the type of data to be transmitted is determined in FIG. 8 (S901). If the data type is text data (= 01), the communication emphasizes correction. (S90
2: FIG. 9). The data type is video data (= 01)
If so, high-speed communication is performed (S903; FIG. 10).

FIG. 9 is a sequence diagram in the case of performing text data communication of the bearer 32K in communication between slave units in this embodiment.

When making a call, the originating PS transmits to the receiving PS together with the call information that the communication to be performed is based on the text data of the bearer 32K (data type = 01) (S600).

Upon receiving the call information, the receiving side PS confirms that the data type is text, and makes the RCR-ST
A sequence according to D28 is performed with the calling side PS,
Communication is performed (S601). At this time, the data communication frame 300 shown in FIG.
2b, the error check unit 302a is used to perform data communication in a frame configuration emphasizing error check.

FIG. 10 is a sequence diagram in the case of performing real-time moving image data communication of the bearer 32K in communication between slave units in this embodiment.

When a call is made, the calling PS transmits to the called PS together with the call information that the communication to be performed now is based on the real-time video data of the bearer 32K (data type = 10) (S700). .

Upon receiving the call information, the receiving-side PS confirms that the data type is a moving image, and checks the RCR-STD2
8 is performed with the originating PS to perform communication (S701). At this time, the data communication frame 300 shown in FIG. 3 is configured, the text data portion at that time is set to 301b, and the error check unit is set to 301a, and a frame configuration that emphasizes high speed is used to perform data communication.

As described above, when data communication is performed between slave units, communication between slave units emphasizing error correction or high-speed performance is emphasized by optimally changing the frame configuration related to error correction depending on the type of data. Communication between child devices can be performed, and there is an effect that waste of data communication can be eliminated.

In the first embodiment, the frame structure of data communication (error check unit) is performed according to the data type.
Has been changed, but it is also possible to change the error correction according to the importance of the data with the same configuration.

As an example, an error correction method for data communication according to the importance of data will be described with reference to FIG. In the illustrated example, the importance of data is high (11) /
Medium (10) / low (01) is prepared, and a frame shown in FIG. 5 can be selected and configured according to the importance of data. That is, error correction is strictly performed for data having high importance, and high-speed communication is performed for data having low importance by increasing the data portion as compared with error correction.

In FIG. 11, the communication with no data importance (00) performs communication without performing error correction.

FIG. 12 is a flowchart showing the communication operation in this case.

First, in negotiation with the partner PS, the importance of the data to be transmitted is confirmed (S100).
1). Here, the importance of the data is set in advance as management information of the data to be transmitted, and the transmitting PS judges this and notifies the receiving PS, and the transmitting side and the receiving side perform an error correction method. Is to match.

If it is determined in the data importance table of FIG. 11 that there is no data importance (= 00) (S1002), data communication is performed without performing error correction (S1003), and the data importance is low. If it is determined that (= 01) (S1004), high-speed transmission similar to the above-described moving image is performed (S1005). Further, for example, since the transmission data is a still image, if it is determined that the data importance is medium (= 10) (S1006), the transmission is performed with emphasis on correction over the above-described moving image and over the speed of text data as described above (S1)
007) Further, if it is determined that the data importance is high (= 11) (S1008), the transmission with the emphasis on correction similar to the above-described text data is performed (S1009).

As a result, there is an effect that reliable data communication can be performed for data with high importance, high-speed communication can be performed for data with low importance, and radio resources can be used effectively.

Further, in the above embodiment, as shown in FIG. 4, the data type is represented by the first and second bits of the fifth octet of the information element part of the control frame. The same effect can be obtained even if the data type and the importance of data are notified. In addition, although PHS communication between slave units has been described as a communication medium, the same effect can be obtained when the present invention is applied to other wireless communication between terminals.

[0051]

As described above, according to the present invention,
When performing communication between slave units, communication is performed by appropriately selecting a plurality of error correction means, so that it is possible to select a suitable error correction in accordance with the type of data and the importance of the data, thereby improving efficiency. There is an effect that it is possible to perform various data communications.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a wireless terminal of the wireless communication system in the embodiment.

FIG. 3 is an explanatory diagram showing a relationship between slots used in a wireless communication system and a configuration of a data frame according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an information part of a control slot when performing communication between slave units in the embodiment.

FIG. 5 is an explanatory diagram showing a frame configuration when data communication is performed between slave units in the embodiment.

FIG. 6 is a flowchart illustrating an operation of a receiving side PS when performing communication between slave units in the embodiment.

FIG. 7 is a sequence diagram in the case of performing communication by voice in communication between child devices in the embodiment.

FIG. 8 is a flowchart illustrating an operation when a correction method is selected in communication between slave units in the embodiment.

FIG. 9 is a sequence diagram in the case of performing text data communication of the bearer 32K in the communication between child devices in the embodiment.

FIG. 10 is a sequence diagram in the case of performing real-time moving image data communication of the bearer 32K in communication between child devices in the embodiment.

FIG. 11 is an explanatory diagram showing the contents of bit coding indicating the data importance used in another embodiment of the present invention.

FIG. 12 is a flowchart illustrating an operation when a correction method is selected in communication between slave units according to the other embodiment.

[Explanation of symbols]

 100: control slot, 101: physical slot, 102: data communication frame configuration, 102a: data section, 102b: error check section, 102c: control information section.

Claims (14)

[Claims] 1. A digital data communication system in which a transmitting terminal and a receiving terminal communicate using a wireless communication transmission path, wherein the transmitting terminal includes two or more data error correction means,
Selecting means for selecting the error correction means, the receiving terminal, two or more data error correction means,
And a selecting means for selecting the error correcting means. 2. The data communication system according to claim 1, wherein the transmitting terminal and the receiving terminal have a voice communication mode and a data communication mode, and select data error correction means in the data communication mode to correct data error. A digital data communication system, comprising: 3. The transmitting terminal according to claim 1, wherein the transmitting terminal selecting unit selects the data error correcting unit of the transmitting terminal according to the type of transmission data or the importance of the data. The digital data communication system, wherein the means selects the data error correction means of the receiving terminal according to the type of data transmitted by the transmitting terminal or the importance of the data. 4. The transmission-side terminal and the reception-side terminal according to claim 1, wherein the transmission-side terminal and the reception-side terminal include, as the data error correction unit, a first error correction unit that emphasizes error correction over high-speed data communication; A digital data communication system comprising: a second error correction unit emphasizing high-speed data communication. 5. The data communication system according to claim 4, wherein said first error correction means and said second error correction means comprise a data part for storing transmission data in a data communication frame having a predetermined configuration. A digital data communication system, which is realized by changing the number of bits allocated to an error check unit for storing a code. 6. The error correction code according to claim 5, wherein the first error correction means emphasizing error correction uses a Reed-Solomon code, and the second error correction means emphasizing high-speed performance uses a CRC code. A digital data communication system characterized by using: 7. The receiving terminal according to claim 4, wherein the transmitting terminal has a notifying unit that notifies the receiving terminal of an error correcting unit selected by the selecting unit of the transmitting terminal. Means for selecting the first error correction means and the second error correction means according to the error correction means notified by the notification means from the transmitting terminal. . 8. The digital data communication system according to claim 1, wherein the transmitting terminal and the receiving terminal are PHSs. 9. The digital data communication system according to claim 8, wherein the transmitting side terminal and the receiving side terminal perform data communication by communication between slave units. 10. A digital data communication terminal for performing communication between slave units using a wireless communication transmission path with a partner terminal, wherein two or more data error correction means and said error correction means are selected. A digital data communication terminal comprising: a selection unit. 11. The digital data communication terminal according to claim 10, wherein said selecting means selects said data error correcting means in accordance with a type of transmission data to be transmitted to a partner terminal or importance of data. 12. The digital data communication terminal according to claim 10, wherein said selecting means selects said data error correcting means according to the type of data transmitted by the partner terminal or the importance of the data. 13. A digital data communication method in which a transmitting terminal and a receiving terminal communicate using a wireless communication transmission path, wherein the transmitting terminal is one of two or more data error correction means. And performing data transmission, wherein the receiving terminal selects one of the two or more data error correction means to perform data reception. 14. The digital data communication method according to claim 13, wherein the transmitting side terminal and the receiving side terminal perform data communication by communication between slave units.