JPH0758955B2 - Wireless data communication system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to wireless data communication, and more particularly to wireless data communication between a base station and a mobile station.

(Prior Art) Conventionally, in this type of data communication, the responding station sends back an affirmative response (ACK) or a negative response (NAK) to the data transmitted by the calling station, or A so-called multiple transmission majority decision system is adopted in which a calling station sends the same data multiple times and a response station makes a majority decision on the multiple sent data to obtain correct data.

(Problems to be Solved by the Invention) By the way, in the above-mentioned ACK / NAK method, if the time required to set up the line becomes long, it is necessary to lengthen the preamble signal. In this case, there is a problem that the data throughput is significantly reduced.

On the other hand, the above-mentioned multiple transmission majority decision method has a problem that the processing on the receiving side becomes complicated, resulting in a large RAM capacity.

(Means for Solving Problems) A wireless data communication system according to the present invention is a wireless communication system in which a wireless circuit performs mutual data communication between complicated wireless devices, and the wireless devices transmit in a transmission mode state. An error detection code is added to data to be encoded, error correction coding is performed including the error detection code, and a frame forming means for forming a frame and a preamble for starting rotation at the time of transmission A transmitting means for transmitting the signal for a required length of time, repeating the frame for a predetermined number of times in advance and continuously transmitting the frame, and a receiving means for successively receiving the frame transmitted in the reception mode state, Each time the frame is received, the frame is subjected to error correction by the error correction code, and then error detection by the error detection code is performed. As a result, if there is no error, the data is valid, other frames are ignored, and if an error is detected as a result of the error detection, the frame in which the error is detected is invalidated, and the frames are sequentially received for each reception. It is characterized in that it has a detecting means for performing the error correction and the error detection on a frame and repeating the error detection until a valid frame is received or a prescribed number of frames are received.

(Example) Hereinafter, the present invention will be described with reference to examples.

First, a wireless communication system to which the present invention is applied will be described with reference to FIGS. 1 to 5.

As a wireless communication system to which the present invention is applied, as shown in FIG. 1, a system in which a plurality of terminal stations (mobile stations) 1 and a central station 2 are directly connected by a wireless line, as shown in FIG. A system in which a plurality of terminal stations 1 and a central station 2 are connected by a wireless line via a relay station 3, and as shown in FIG. 3, a plurality of terminal stations 1 and a central station 2 are connected to relay stations 3 and 4 There are systems and the like that are connected by a wireless line via.

As shown in FIG. 4, the terminal station and the central station have a data processing unit 5,
The transmitter 6 and the receiver 7 are provided. The data generated by the data processing unit 1 is transmitted as a radio wave by modulating the wireless carrier wave by the transmitting unit 2. On the other hand, the received radio waves are demodulated by the receiving section and passed to the data processing section 1 as data.

As shown in FIG. 5, the relay station is provided with a receiving unit 8 and a transmitting unit 9. The radio wave received by the receiving unit 8 is once demodulated into data, and a wireless carrier wave is used as a modulation signal of the transmitting unit 9. Modulate and retransmit.

Now, when sending inquiry data from the terminal station to the central station via the relay station, referring to FIG. 9, the data processing unit of the terminal station first calculates the error detection code, and the error detection code is sent to the data to be sent. After adding, error correction coding is performed. Furthermore, by adding an idling signal and a frame synchronization signal,
The signal format shown in FIG. 3B is configured to be a frame.

As shown in FIG. 6 (a), the transmission of the inquiry signal is performed by first transmitting the preamble signal for the time required to set up the line, and then transmitting the first frame A, the second frame B, and the second frame B. The third frame C is transmitted in order (frames A, B, and C have the same contents. That is, FIG. 6B).
The signal format is shown in). That is, the frame having the same content is repeated three times and transmitted.

By the way, the inquiry signal transmitted from the terminal station is relayed by the relay station and transmitted to the central station as shown in FIG.
As shown in FIGS. 8A and 8B, the preamble signal is deleted by the time required for the relay station to rise. The relayed inquiry signal is received by the receiving unit of the central office, and at this time, the time required for the receiving unit to rise is reduced (8th embodiment).
Figure (c)).

Referring to FIG. 10, the data processing unit of the central office first receives the first frame A by detecting the frame synchronization signal, corrects the error based on the error correction code, and thereafter, for error detection. The error is detected by the code. If there is no error as a result of this error detection, frame A is treated as a correct signal and frames B and C are ignored. On the other hand, if an error is detected in the frame A, the frame A is invalidated, then the error correction and error detection of the frame B are similarly performed, and the same processing as described above is performed. Further, when the frame B is invalidated, the frame C is processed. Then, the central office receives the AC for receiving these signals (frames A, B, and C).
Do not reply K or NAK. The response signal from the central station is also sent to the terminal station in the same manner.

Here, the data communication method used in the above-described embodiment and the conventional AC
Comparing the transmission times of the K / NAK system, the conditions are a signal rate of 16KBPS, a required data length of 800 bits (100 bytes), a coding rate of 60% including error correction and detection, an idling signal and a frame. A total of 100 bits including the synchronization signal and a line startup time of 500 ms. In this case, since the time required for signal transmission is almost the signal length, it becomes 500 ms + {(800 bits ÷ 0.6) + 100 bits} × 3 ÷ 16000 bits / s = 769 ms.

On the other hand, the data length required for ACK or NAK is 80 bits (10
Byte), the time required for signal transmission is almost equal to the sum of signal lengths [500ms + {(800 bits ÷ 0.6) + 100 bits} ÷ 16000 bits / s] + [500ms + {(80 bits ÷ 0.6) +100 bits} ÷ 16000 bits / s] = 11
It will be 00ms.

As described above, the data communication method according to this embodiment uses the conventional AC
The transmission time is shorter than that of the K / NAK method. That is, the throughput is short.

(Effect of the Invention) As described above, in the data communication method according to the present invention, data is transmitted in multiples, and it is determined whether or not the data are correct in order and the data after the normal data is ignored at the correct time. Therefore, throughput can be increased while maintaining reliability.

[Brief description of drawings]

1 to 3 are diagrams showing a wireless communication system to which the present invention is applied, FIG. 4 is a device system diagram of a terminal station and a central station,
FIG. 5 is a device system diagram of a relay station, FIG. 6 (a) is a diagram showing an inquiry signal format, FIG. 6 (b) is a diagram showing a frame signal format, and FIG. 7 is an inquiry signal and a response. FIGS. 8A, 8B, and 8C show signal reception timings, respectively, showing an output signal format of a terminal station, an output signal format of a relay station, and an output signal format of a central station, FIG. 9 is a flow chart showing signal transmission processing on the transmitting station (terminal station) side,
FIG. 10 is a flow chart showing a signal transmission process on the receiving station (central office) side. 1 ... Terminal station, 2 ... Central station, 3,4 ... Relay station, 5 ... Data processing section, 6,9 ... Transmission section, 7,8 ... Reception section

Claims (1)

[Claims] 1. In a wireless communication system in which a plurality of wireless devices mutually perform data communication by a wireless circuit, the wireless device adds an error detection code to data to be transmitted in a transmission mode state. A frame constructing means for constructing a frame by performing error correction coding including the error detecting code, and at the time of transmission, first transmit a preamble signal for establishing a line for a length of time, and then transmit the frame. Repeat a predetermined number of times,
Transmission means for continuous transmission, reception means for successively receiving the frames transmitted in the reception mode state, error correction by the error correction code for the frame each time the frame is received, and then error by the error detection code After detection, if there is no error as a result, the data is valid, other frames are ignored, and if an error is detected as a result of the error detection, the frame in which the error is detected is invalid. A detection unit that sequentially performs the error correction and the error detection on the frame for each reception, and repeats the error detection until a valid frame is received or a prescribed number of frames are received. A wireless data communication system characterized in that