JPS6129230A - Packet communication system - Google Patents

Abstract

PURPOSE:To make communication possible even when an error rate on the transmission line is extremely large by converting 1 data bit to plural multiple- point bits and sending to the interface of a packet communication device and a transmission line for communication, and restoring it to former state in a receiving side. CONSTITUTION:One bit of flag pattern F is three bits multiple-point sample in interface parts 101, 105 with transmission lines 110, 112 from input/output devices 102, 103 in packet communication devices 101, 104, and transmitted through the device 102 and an inter-office transmission line 111. Multiple point sample bit pattern is received by the device 103 and reproduced in original bit pattern F by majority logic. Errors in each data bit D can be corrected by frame check bit FCS in the packet format and high quality data communication is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a packet communication system and a packet communication system that is applied when the quality of the inter-office transmission path is poor, such as in an outdoor system.

(Prior art) In packet communication, if the transmission path for communication is well managed and a good error rate can be maintained, high-quality data communication is performed, but if the error rate on the transmission path worsens for some reason,
The packet retransmission rate snowballs and the traffic in the network tends to increase rapidly.

(Object of the Invention) An object of the present invention is to provide a packet communication system that allows communication even when the error rate on the transmission path is extremely low.

(Structure of the Invention) According to the present invention, in a communication network that communicates data in the form of packets via a communication transmission line, one data bit is transmitted at multiple points at the interface between the packet communication device and the communication transmission line. It is equipped with an input/output device that has a multi-point sampling function for converting into bits and a multi-point sampling function for its inverse, and has means for setting the number of multi-point samplings on the input/output device, and the communication speed on the communication transmission line is A packet communication system is obtained in which the receiving device has means for determining the number of multiple points set on the transmitting side by counting the number of "I"s included in the flag pattern.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a system diagram of an embodiment of the present invention. 100 and 1
04 is the opposing packet communication device. Further, 102 and 103 indicate input/output devices having a multi-point sampling mechanism and a multi-point sampling mechanism corresponding to the packet communication devices 100 and 104, respectively. 110 and 112 are packet communication devices 100;

104 and the input/output devices 102 and 103, respectively; "1" indicates an interoffice transmission path. Also 101 and 1
05 indicates a line interface section of each of the packet communication devices 100 and 104, and this interface section 1.
Data is sent between stations by 01 and 105. In addition, these interface units 101 and 105 connect signal lines 113 to their corresponding input/output devices 102 and 103, respectively.
114, and performs the transmission of signals necessary for data transfer.

FIG. 2 shows a frame format diagram illustrating the principle of the present invention. Figure 2 (1) shows the format when communicating in the normal packet format, and the FIIi" flag 1 indicates the delimiter in the data chain. A is the party to communicate with with 1 address 1. It indicates the destination address.C
1 control 1 indicates the packet control function. D is 1 data 1, and the communication message is divided into certain lengths and inserted into these parts for transmission. Fe2 is the I7 frame check signal 1, which has a function of checking for code errors in the entire 1 pack.

Figure 2 (2) shows the frame format shown in Figure 2 (1) with actual bit patterns, and the 7 lag pattern is as shown in Figure 2 (2). ”
Communication is performed using a bit pattern of N01. Since A, C, etc. can take any arbitrary pattern, they are not shown here.

FIG. 2(3) shows the bit pattern after the multi-point sampling of the bit pattern in FIG. 2(2) and the multi-point sampling on the inter-office transmission line "1" to be sent out. FIG. 2 (3) shows a case where the number of multiple points is 3. i.e. 0→000,1
→It is expressed with 3 bits of “1”.

The multi-point sampled bit pattern is received by the receiving input/output device 103 on the inter-office transmission path "1", and is shown in FIG. 2 (2) using a mechanism based on the principle of majority logic. Play the bit pattern.

The majority decision circuit is well known and will not be described in detail here, but even if, for example, one of the three bits on the inter-office transmission line "1" is erroneous, it can be resolved by making a 2-to-1 majority decision. The correct bit waveform can be reproduced.

Since one data bit is sampled at multiple points and sent out in this way, the speed after sampling at multiple points is multiplied by the number of points. That is, if the original communication speed is, for example, 1200 bps and the number of multiple points is 3, the speed of the inter-office transmission path must be 3600 bps. However, in general, the portion corresponding to the inter-office transmission line involves many things in terms of distance and quantity of transmission equipment, so it is not easy to change the speed of the inter-office transmission line. I can't.

The present invention fixes the speed of the inter-office transmission line, which is easily affected by the external environment, and changes the number of multi-point samplings in response to changes in the transmission error rate of the inter-office transmission line. On the side, the number of multi-point samplings is detected by detecting the flag pattern, and subsequent data reception is made possible.

In other words, as a feature of packet communication, the flag pattern is '0'1''1'o+' as shown in Figure 2 (2).
This pattern is determined to be 7-ormat, and is configured so that this pattern will never appear in the data. This is done by using a well-known 0 bit insertion/removal mechanism that inserts a 0 whenever there are five consecutive 1's in the data, and on the receiving side, if there are five consecutive 1's, the next 0 is removed and the data is assembled.

Therefore, six consecutive 1's are always interpreted as a 72 Tsugu pattern. Using this, we can count that the number of 1's in the data group is 18, as shown in Figure 2 (3).Since K is 3 times 6, we know that the number of points is 3. It becomes possible to interpret and receive subsequent data in the same way.

Similarly, FIG. 3 shows a case where the number of points is 5, and it can be determined that the number is 5 by counting 30 consecutive 1's.

On the receiving side, by applying a majority logic circuit using well-known technology, subsequent data reproduction is performed for each data bit, and any errors in each data bit are corrected by frame check bit FC8 in the packet format. This allows very high quality data communication.

(Effects of the Invention) As explained above, the present invention has the effect of enabling communication even when the error rate on the transmission path is extremely low.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a seven-frame format diagram of an embodiment of the invention, and FIG. 3 is a frame format diagram of another embodiment of the invention. 100.104---Packet communication device, 102
, 103... Input/output device, 101, 105...
...Interface section. 1. -17 Agent Patent Attorney Uchihara I, H..., I Town

Claims (1)

[Claims] In a communication network that communicates data in the form of packets via a communication transmission line, the interface between the packet communication device and the communication transmission line has a multi-point sampling function that converts one data bit into multiple multi-point bits. On the other hand, an input/output device having a multi-point resampling function is equipped with a means for setting the number of multi-point sampling in the input/output device, and the communication speed on the communication transmission path is fixed, and the receiving device has a flag pattern. A packet communication method characterized by having means for determining the number of multiple points set on the transmitting side by counting the number of "1"s included.