JPH10107715A - Data communication system and communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select automatically a transmission speed of data communication using a radio channel based on an actual measurement of an error rate of reception data in real time. SOLUTION: A ROM 2 and a RAM 3 are mounted on a data processing section (CPU) 1. MODEM sections 6, 7 exchange data through a radio channel and the MODEM (demodulation section) 7 converts an analog signal received from a receiver 11 into a digital signal, which is given to the CPU 1. Furthermore, the MODEM section 6 converts a digital signal from the CPU 1 into an analog signal, which is outputted to a transmitter 10. A transmission clock changeover section 8 is a clock generating section to select a transmission speed of the MODEM sections 6, 7 and controlled by the CPU 1. The CPU 1 provides optimum transmission speed information based on a data error rate from a receiver side, the receiver side selects the transmission speed based on the optimum transmission speed information and the transmitter side selects the transmission speed simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio line (radio wave).
TECHNICAL FIELD The present invention relates to a data communication system for automatically switching to an optimum data transmission speed in a data communication utilizing the communication method and a communication device used for the data communication.

[0002]

2. Description of the Related Art Conventionally, the transmission speed in data communication using a wireless line is fixed speed, is switched by operation, or is automatically compared with its own internal clock at a preset time. There is something to switch.

Normally, when transmission conditions of radio waves are good, a high transmission speed is set for data transmission, and when transmission conditions are bad, a low transmission speed is set, whereby errors in data transmission can be reduced. It is.

[0004] However, since the spatial state changes every day depending on the time zone and the weather, when the spatial state is deteriorated (propagation of radio waves is deteriorated), if the set transmission speed is high, the signal is transmitted on the receiving side. A lot of data may be missing.

When the receiving side is a moving body such as an aircraft, a ship, a vehicle, or the like, the propagation state changes depending on the current moving position, and it is difficult for the transmitting side to grasp the receiving state.

[0006]

As described above, in the conventional wireless data transmission, it is difficult for the transmitting side to determine and switch the optimum data transmission speed on the receiving side, and furthermore, due to the constantly changing transmission state. However, there is a problem that it is difficult to switch in real time.

An object of the present invention is to provide a system capable of automatically switching the transmission speed in data communication using this wireless line based on a real-time measurement of the error rate of received data.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to provide a receiving station for transmitting the data error rate information to a transmitting station by accumulatively measuring the number of errors in received data for a certain period of time, and A transmission station that controls the switching of the data transmission rate by determining the optimum data transmission rate for the current propagation state of the radio wave.

Further, the above object is achieved by providing a communication device with means for automatically switching a data transmission speed to an optimum transmission speed based on error rate information of received data from a receiving side.

[0010] According to the above means, since the error rate information is transmitted from the receiving side to the transmitting side, the data transmission speed can be switched to the optimum value in real time based on the error rate information. As a result, the receiving side can always receive high-quality data, and does not have to make a retransmission request to the transmitting side.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of a communication device used in the data communication system of the present invention. The CPU is used for the data processing unit 1 to perform each control. CP
A ROM where program codes are stored around U
2. RA used by the program to execute each control
M (volatile RAM and nonvolatile RAM) 3 is mounted. The operation unit / display unit 4 is used for key input for setting communication conditions, display of the settings, and operation monitoring.
The DTE interface unit 5 exchanges data with the external terminal device 9 and the like.

Transmission media include serial, LAN, and modem. The modem units 6 and 7 exchange data over a wireless line. An analog signal received by the antenna 12 from the antenna 13 and input from the receiver 11 is modem (demodulation unit)
At 7, the signal is converted into a digital signal and input to the CPU 1. A digital signal from the CPU 1 is converted into an analog signal by a modem (modulation unit) 6 and output to an antenna 13 from an antenna 12 via a transmitter 10.

The transmission clock switching unit 8 includes modem units 6 and 7
This is a clock generation unit for switching the transmission speed of the data. The transmission speed can be changed by switching the clock. Switching of the clock is controlled by the CPU 1.

[0015] In the configuration of the communication system according to one embodiment of the present invention using the above-described communication device, broadcast data is transmitted from a transmitting station to a plurality of receiving stations. The receiving station has a data error correction function. For example, as one of the error correction functions, a BCH (Bose) capable of correcting an error up to 2 bits is provided.
(Chaudhuri Hoquenghem) code. In this case, the receiving station can detect and correct errors of up to 2 bits for one word data. (Note that the BCH error correction code and the error correction method are already known.)
The data input from the TE 9 is subjected to data processing such as BCH processing for data to be transmitted to the wireless line by the data processing unit 1, and the corresponding error rate information is transmitted to the data destination station by R.
The optimum transmission speed information is obtained by referring to the AM3, and transmitted at the standby transmission speed together with the synchronization signal. As the standby transmission speed, the lowest transmission speed that can be transmitted by the communication device is fixedly used.

FIG. 2 shows the transmission timing switching timing and the data transmission format configuration. In the receiving station, the data start position is first detected by the synchronization signal, and the corresponding transmission speed information is transmitted by the transmission speed information transmitted thereafter. The transmission clock switching unit 8 is automatically switched to a clock that matches the speed, and again waits for a synchronization signal. At the same time, the transmitting station also switches the transmission clock switching section 8 to the corresponding clock. The subsequent resynchronization signal is a signal for resynchronizing after both communication devices switch the transmission speed.

After transmitting the resynchronization signal, the transmitting station transmits data, and transmits a stop signal when data transmission is completed. This stop signal is a signal for recognizing the end of data transmission. When the receiving station recognizes the stop signal, the transmission speed is automatically switched to the standby transmission speed to prepare for the next data reception.

The receiving station calculates an error rate from the received data. That is, the error rate is obtained by accumulatively measuring the number of errors detected by the error detection for a certain period of time. The obtained error rate data is transmitted to the transmitting station in the transmission format shown in FIG. In this case, the lowest transmission speed that can be transmitted by the system is used as the transmission speed.

The transmitting station that has received the error rate information records the information in a memory (RAM 3) managed for each station address in FIG. The data processing unit 1 refers to the error rate information from the plurality of receiving stations to comprehensively determine, selects the optimum transmission speed information, transmits the information to the receiving station, and sets the clock of the transmission clock switching unit 8 to the corresponding transmission speed. Switch to match. If the destination of the data is an individual station, data transmission is performed by selecting an optimum transmission speed based on error information in a memory (RAM 3) corresponding to the receiving station.

As the error rate information to be transmitted, the number of errors accumulated and measured during a fixed time may be transmitted as error rate information.

[0021]

As described above, according to the present invention, the receiving station can always receive high-quality data at the optimum transmission rate for the current state of the radio line, and can transmit data from the receiving station to the transmitting station. The number of retransmission requests is reduced, and effective use of wireless lines can be expected. At the transmitting station, the work load of the operator for switching the transmission rate can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a communication device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a transmission rate switching timing and a data transmission format.

FIG. 3 is a configuration diagram of an error rate information transmission format.

FIG. 4 is an explanatory diagram of an error rate memory.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Data processing part, 2 ... ROM, 3 ... RAM, 4 ... Operation part / display part, 5 ... DTE interface part, 6 ... Modem (modulation part), 7 ... Modem (demodulation part), 8 ... Transmission clock switching part , 9 ... terminal device, 10 ... transmitter, 11 ... receiver, 12 ... antenna, 13 ... antenna.

Claims (3)

[Claims] In a data communication system using a wireless line, a receiving station for transmitting error rate information obtained by cumulatively measuring the number of errors in received data to a transmitting station to a transmitting station, and based on the transmitted error rate information. A data communication system comprising: a transmission station that determines a data transmission rate optimal for a current radio wave propagation state and controls switching of the data transmission rate. 2. The control for switching the data transmission rate of the transmitting station transmits the current optimum data transmission rate information to the receiving station, and the receiving station switches the transmission rate based on the transmitted optimum data transmission rate information. The transmission station also switches the transmission speed at the same time.
A data communication system as described. 3. A communication apparatus for use in a data communication system using a wireless line, characterized by comprising means for automatically switching a data transmission rate to an optimum transmission rate based on error rate information of received data from a receiving side. Communication device.