JPH01189247A - System for controlling data transmission system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a data transmission system control method that selects whether or not to add an error correction code to a data transmission frame transmitted and received in a data transmission system depending on the transmission error rate. If the transmission error rate is below a certain value, a data transmission frame is constructed without adding an error correction code, and if the transmission error rate is above a certain value, a data transmission frame is constructed with an error correction code added. The purpose of the present invention is to provide a method for efficiently transmitting a data transmission frame by adding an error correction code to the data transmission frame at the transmitting station in the data transmission system in which the data transmission frame is transmitted and received between the transmitting station and the receiving station. a transmission error rate monitoring circuit for monitoring the transmission error rate of the data transmission frame at the receiving station; and a transmission error rate monitoring circuit for monitoring the transmission error rate of the data transmission frame at the receiving station; and a selection circuit for selecting whether or not to add an error correction code.

[Industrial application field]

The present invention relates to a data transmission system control method that selects whether or not to add an error correction code to data transmission frames transmitted and received in a data transmission system depending on the transmission error rate.

Conventionally, in order to detect transmission errors in data transmission frames and correct error data, redundant bits are added and transmitted, and the receiving station checks the correlation between the redundant bits and the data to identify the normality of the data. However, there was a desire to add redundant bits and improve transmission efficiency as the amount of data transmitted increased.

[Conventional technology]

As mentioned above, conventionally, as a method for correcting bit errors in a data transmission frame that occur during transmission, a transmitting station adds an error detection code, that is, a parity bit, or a CRC code to the data of the transmission frame and sends it out. , the normality of the data is determined by checking the correlation between the frame data transmitted at the receiving station and the error detection code.

If an error is detected, the receiving station discards the frame and requests the transmitting station to retransmit it.

In general, when transmission errors occur, error bits occur sporadically in data, and most of the errors are l-bit errors.
Error Check and Correct
ion ) code is added to automatically correct data in the case of a 1-bit error.

[Problem to be solved by the invention]

If an error occurs in a transmission frame, the transmission delay of at least one round trip of the transmission frame is required before retransmission is started;
There is a loss of time required to check the data.

If the retransmission timing at the transmitting station is started by the timeout of the response waiting timer from the receiving station,
Extra time will be lost waiting for timeouts.

These time losses can be reduced if the transmission error rate is small.
It is possible to ignore the effect on average transmission efficiency.

However, if the time loss due to one retransmission is large and the transmission error rate becomes large, it cannot be ignored as a factor in reducing the average transmission efficiency.

The increase in the transmission error rate may be caused by deterioration of the transmitting station driver, deterioration of the receiving station receiver, deterioration of the usage environment of the transmission line, etc.

When the transmission error rate gradually increases, it is difficult to take countermeasures because it is difficult to noticeably affect the average transmission efficiency.

Furthermore, when an error correction code is added to the data, l-bit errors are corrected and the number of retransmissions is reduced, but the transmission efficiency is also reduced by the addition of redundant bits.

The present invention was created in view of these points, and includes monitoring the transmission error rate, and configuring a data transmission frame without adding an error correction code when the transmission error rate is below a certain value, If the transmission error rate is above a certain value, an error correction code is added to form a data transmission frame,
The purpose is to provide a method for efficient transmission.

[Means to solve the problem]

In order to achieve the above-mentioned purpose, an error correction code adding circuit for adding an error correction code to a data transmission frame is provided at the transmitting station, a transmission error rate monitoring circuit for monitoring the transmission rate; A data transmission system is configured, including a selection circuit that selects whether or not the data is necessary.

[For production]

A transmission error rate monitoring circuit is provided at the receiving station, and the transmission error rate is calculated by constantly integrating the number of errors in data transmission frames transmitted from the transmitting station over a predetermined period of time.

Then, it is monitored by comparing it with a certain predetermined value, and if the transmission error rate exceeds this value, it is notified to the transmitting station, and the transmitting station activates the error correction code addition circuit to correct errors in the data transmission frame. Add a sign.

Furthermore, when the transmission error rate is less than this value, the transmitting station is notified, and the transmitting station stops the error correction code addition circuit and configures a transmission frame without adding an error correction code to the data transmission frame.

That is, an error correction code is automatically added to or deleted from a transmission frame depending on the transmission error rate.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the data transmission error correction system of the present invention.

Data is n bits, ECC code (error correction code)
If not added, a 1-bit parity bit is added, and a basic frame is composed of fi+l bits.

When adding an ECC code, an ECC code of m vias is added to n bits of data, and n+m bits are used as a basic frame.

In FIG. 1, power is turned on and the transmission system is activated.

In the transmitting station T, n bits of transmission data are set in the transmission data register 1.

At system startup, the error detection code selection circuit 4 selects the output of the parity bit addition circuit 2 and does not add an ECC code (ECC code off mode).

A parity bit is added to the transmission data n to form a data transmission frame (hereinafter referred to as a transmission frame), and the data is manually input to the parallel-to-serial conversion register 5.

The parallel-to-serial conversion register 5 converts the transmission frame into a serial code string and sends it to the transmission diagram vA6.

When the transmission frame is manually entered into the serial/parallel conversion register 7 at the receiving station R, it is again converted into a parallel code string and set in the reception frame register 9 via the synchronization control circuit 8.

The synchronization control circuit 8 performs synchronization processing to receive transmission frames without ECC codes.

Since no ECC code is added to this transmission frame, synchronization can be achieved.

However, if an ECC code is added to the transmitted transmission frame, synchronization cannot be achieved in this state, and if synchronization cannot be achieved within a certain period of time, a synchronization process is performed to receive a frame with an ECC code.

The synchronization control circuit 8 thus changes the synchronization processing method at predetermined times, performs synchronization processing that matches the format of the received transmission frame, and notifies the error detection code circuit 10 of the transmission frame format.

The error detection bit of the transmission frame in the reception frame register 9, that is, the ECC code or parity code, is checked for correlation with the data in an ECC check circuit 11 and a parity check circuit 12 together with the data. When a bit error is detected, the error correction circuit 13 corrects the data to a normal value.

The data of the normally received transmission frame is stored in the reception data register 14 by the circuit bus selected by the error detection code circuit 10.

On the other hand, the error rate monitoring circuit 15 counts the number of errors in the transmission frame within the time specified by the timer (calculates the error rate, compares it with a certain specified value, and if the error rate exceeds this specified value , or if divided, the transmitting station T is notified.

In the former case, an ECC code is generated by the error detection code selection circuit 4 of the transmitting station T, and the ECC code addition circuit 3 generates the ECC code.
In the latter case, the parity pit adding circuit 2 generates parity bits to form a parity-coded transmission frame and sends it to the transmission line 6.

FIG. 2 is a flowchart of the operation of the transmitting station in the above-mentioned embodiment, and FIG. 3 is a flowchart of the operation of the receiving station.
3(a) shows the firmware of the receiving station, and FIG. 3(b) shows a flowchart of the operation of the hardware.

According to the present invention, when many errors occur during transmission, an ECC code is added to the transmission frame, and the receiving station performs correction processing, thereby reducing retransmission requests to the transmitting station.
When there are few errors in transmission, no ECC code is added and the transmission frame is shortened accordingly, improving transmission efficiency.

That is, transmission efficiency can be improved regardless of the error occurrence state in transmission.

It goes without saying that the error rate monitoring circuit 15 may be provided at the transmitting station T, and the error coding method may be selected in response to a retransmission request signal from the receiving station R.

Alternatively, the receiving station may simply notify the transmitting station of the number of errors per unit time, and the transmitting station may process the notified data and select the error coding method.

〔Effect of the invention〕

As described above, according to the present invention, an error code to be added to a transmission frame can be automatically selected depending on the transmission error rate, and the average transmission rate can be improved, which is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the control method of the data transmission system of the present invention, FIG. 2 is a flowchart of the operation of the transmitting station in FIG. 1, and FIG. 3 is the operation of the receiving station in FIG. FIG. In the figure, 1 is a transmission data register, 2 is a parity pit addition circuit, 3 is an ECC code addition circuit, 4 is an error detection code selection circuit, 5 is a parallel-to-serial conversion register, 6 is a transmission line, 7 is a serial-to-parallel conversion register, 8 is a synchronization control circuit, 9 is a reception frame register, 10 is an error detection code circuit, 11 is an ECC check circuit, 12 is a parity check circuit, 13 is an error correction circuit, 14 is a reception data register, and 15 is an error rate monitoring circuit. be. 4 Tomano 77-4 r Ao〃 made (a An Bun I evening station ↑〃 made / 170-thousand τ-th) 3rd figure 77 - 4 r Ao〃 made / 170-thousand τ-th figure 3

Claims (1)

[Claims] In a data transmission system that transmits and receives a data transmission frame between a transmitting station and a receiving station, the transmitting station includes an error correction code adding circuit (3) that adds an error correction code to the data transmission frame, and the receiving station transmits the data. A transmission error rate monitoring circuit (15) monitors the transmission error rate of the frame, and the error correction code adding circuit (3) uses the output of the transmission error rate monitoring circuit (15) to add an error correction code to the data transmission frame. Selection circuit for selecting necessity (4)
A data transmission system control method comprising: