JPS60244154A - Automatic retransmission system - Google Patents

Abstract

PURPOSE:To shorten the transmission time and to improve the compression factor by deciding the normal end of the relevent frame at a time point when a delay of data compression is completely clear and therefore disusing the frame at the reception side and reducing the input of ''fill''. CONSTITUTION:A check part 11 for shift-down condition which feeds the control of reproduction of Ack/Nack (reception) is provided at an ARQ part 10 of a transmission part of an automatic retransmission system together with a buffer 12. A framing P/S conversion part 13 is connected to the buffer 12. No ''fill'' nor ''request'' are used between the buffer 12 and a DCR15, and the framing is carried out while monitoring the data remianing in the buffer 12. Then no ''fill'' is inserted despite reduction of the data in the buffer 12, and the normal framing is continued until to data exists any more. Then the relevant frame is disused at the reception side at a time point when a delay of data compression is completely clear to reduce the input of ''fill''. In such a way, shortens the transmission time is shortened and also the compression factor is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic retransmission system in facsimile transmission.

Figure 2 is a block diagram of a transmitting section in a conventional facsimile machine. In the figure, 10 is an ARQ section, 11 is a shift condition check section, 12 is a buffer, and 13 is a framing P.
/S conversion section, 15 is a DCR section, as is well known, DCR
The data encoded by the section 15 is stored in the buffer 12, and the framing P/S conversion section 13 performs framing and P/S conversion, and transmits the data. Then, check the Ack/Nack signal from the receiving section from time to time,
If Nack (frame reception error) is returned, the frame is retransmitted. Further, it is checked whether the downshift condition is satisfied by counting the number of Ack and N ack, etc., and if the condition is satisfied, the downshift is performed.

When the encoding in the DCR unit 15 is delayed and the buffer in the DHC is about to become empty, the DHC sends Fill Re to the DCR.
Quest is sent, and Fill is received from DCR to compensate for the encoding delay. .

FIG. 3 is a block diagram of a receiving section in a conventional facsimile machine. In the figure, 20 is an ARQ section, 21 is an S/P conversion framing check section, 22 is a buffer, and 25 is a DCR section, as is well known. Remove the framing of the received data and check for errors, and if there is an error, NACK
, when there is no error, returns an Ack, and correctly received frames are stored in the buffer 22 and sent to the DCR unit 5.

As mentioned above, in a facsimile machine, data encoding is performed by DCR, data framing, etc. is performed by ARQ, and when DCR encoding is insufficient and there is no more data to be sent from ARQ, ARQ performs DCR.
RA, send a fill request, F
I'm buying time by filling up ill.

However, it became necessary to send Fill, and the extra Fill
Because ll is inevitably included, the transmission time becomes longer. Also, in the automatic retransmission method for the purpose of reliable data transmission.

In order to increase the compression ratio, the K parameter is set to the maximum limit, Fill
The SMR method (S
Although it can be used in combination with (superModified Read), Fill is inevitably included depending on the document due to processing time.

The present invention was made in view of the above-mentioned circumstances, and was made with the purpose of providing an automatic retransmission system that can reduce the transmission time by minimizing the input of Fill. It is.

DETAILED DESCRIPTION OF THE INVENTION The structure of the present invention will be described below based on examples.

FIG. 1 is a block diagram for explaining an embodiment of the present invention, and the present invention is characterized by a transmitting section.

The receiving section is no different from the conventional technology mentioned above.

In FIG. 1, only the transmitter is shown. The present invention is characterized in that it does not use the Fill Request signal used in the conventional transmitter shown in Fig. 2, and the overall configuration is the same as that shown in Fig. 2. Since this is substantially the same as the prior art, the reference numerals in FIG. 1 correspond to those in FIG. 2, respectively.

Accordingly, in the present invention, processing when the DCR unit 15 is unable to encode in time and there is no data in ARQlo is performed as follows. ARQIO performs HDL framing while monitoring the internal buffer 11, and even if the data remaining in the buffer 11 decreases,
No ill insertion is performed, and normal framing continues until there is no more data to frame. When there is no more tape to send, it is assumed that the frame being sent at that time has not been completed, and that information is sent to the receiving side. Specifically, if empty data is sent as the final data, the receiving side will discard the frame as a short frame error. However, if it happens to be the final data, 2 bytes of empty data are sent and the second byte is used as the final data.

Therefore, in the conventional method, the place to fill is limited to the end of the line, so Fill Re
Quest must be sent early, and even if there is a continuous data string that can cover the compression delay, Fill must be filled.

However, according to the present invention, not only can DCR and ARQ wait until the last minute to determine that compression is delayed, but DCR and ARQ can
There is no need to spend time on st-related processing, processing capacity is increased, and transmission time can be shortened.

As is clear from the above explanation, according to the present invention, F
Since processing related to the ill request is no longer necessary, there is no need to consider delicate factors such as when to issue the fill request and how many bits to fill in the fill. Also, DCR.

ARQ (especially DCR) processing performance is improved. On top of that,
Since it is possible to wait until the last minute to fill in the fill, there are fewer ways to insert the fill than before, which has the advantage of increasing the compression ratio and shortening the transmission time. .

[Brief explanation of drawings]

FIG. 1 is a block diagram of a transmitting section in a facsimile apparatus according to the present invention, FIG. 2 is a block diagram of a transmitting section in a conventional facsimile machine, and FIG. 3 is a block diagram of a receiving section. 10... ARQ section, 11... Shift down condition check section, 12... Buffer, 13... Framing P/S conversion section, 15... DCR section, 20... ARQ
Part, 21...S/P conversion framing check part, 2
2...Buffer, 25...DCR section. Figure 2 Figure 3

Claims (1)

[Claims] The data is sent with appropriate framing, the receiving side checks whether the frame has been received correctly, and provides that information to the sending side. Frames that could not be received are retransmitted, and frames that cannot be received are In the automatic retransmission method, which shifts down the transmission modem rate when certain conditions such as a large number of An automatic retransmission method characterized in that the receiving side discards the frame by not terminating the frame normally.