SU1179366A1 - Device for simulating communication systems - Google Patents

Abstract

A DEVICE FOR MODELING COMMUNICATION SYSTEMS, containing a message generator, the output of which is connected to the first 1 input of the AND element and the information input of the counter of transmitted messages, the output of the AND element connected to the information input of the counter of correctly received messages, the trigger, the first generator of a random sequence of pulses, the counter correctly received distortion, link failure counter, link recovery counter, the setup inputs of all counters are combined and are the setup input of the device The outputs of the counters are connected to the corresponding inputs of the display unit, characterized in that, in order to increase the modeling accuracy, it additionally contains a second generator of a random sequence of pulses, the output of which is connected to the information input of the restoration counter of the communication channel and the first trigger input , the second input of which is connected to the output of the first generator of a random sequence of pulses and the information input of the counter of communication channel failures, the output of the trigger is connected to the second input item I.

Description

The invention relates to communication technology and can be used to simulate errors in the communication channel. The purpose of the invention is to improve the accuracy of modeling through the implementation of the model. Hilbert. The drawing shows a block diagram of the device. The device contains a generator of 1 messages, an element 2, the first generator 3 of a random sequence of pulses trigger 4, 5 counts of transmitted messages, a counter 6 of correctly received messages, a counter 7 of communication channel failures, a counter 8 of restoration of the communication channel, a display unit 9, the second generator 10 of a random sequence of pulses. The device is based on the Gilbert model, which more accurately reflects the real nature of errors in the communication channels. According to the Gilbert model, the communication channel can be in one of two states: good, when errors are impossible, good condition, and in bad, when independent errors occur. , state of failure, having probability (1-). The probability of a change of state during the transmission of each bit (the messages of the information being sent are recorded in the form of a P + matrix. If during transmission (j-th symbol the channel was in a bad state, then when transmitting the jth symbol with a probability (it will remain in in the same state and with probability P. goes to a good state. Similarly, Q is the probability of a good state when transmitting the j-th symbol, if () -1) -th symbol is transmitted via a channel with a good condition, and The likelihood of a change in good condition. The grouping of errors into packets due to the ratio and mi Q P,, O P J which ensure comparative stability of each state. The final probabilities P (a) ir (p1-p) are unconditional probabilities of the appearance of a correspondingly poor and good state, and PJ, P (1 -h) / (P + p) the probability of distortion of the symbol in the channel. With this, the distribution of the length of the intervals between adjacent errors) according to the Gilbert model can be represented as follows: i (i) -A-: j (iA) z (where j - j sequence of undistorted characters; (a-4cpp | r; (2), l {Q-hcif44hpp / 2; (3) A - (: i + p-QW (l-). C) A device for simulating a communication system works as follows. Before When the device starts operating, the control inputs of counters 5-8 receive a control signal that nullifies these counters. Pulse generator 1 builds a sequence of pulses simulating a sequence of characters approaching the first input of AND 2 (into the communication channel). The number of pulses arriving at the output of the pulse generator 1, is counted by the counter 6. The generators 3 and 10 are designed for The impulses from the output of the generator 3 of a random stream of pulses arriving at the first input of trigger 4 cause the transition of trigger 4 to the state O. At the same time, the control signal from the output of trigger 4 element 2, prohibits the passage of signals through element 2. The poor state of the communication channel is thus simulated. The pulses from the generator output 10 of a random stream of pulses arriving at the second input of the trigger 4 cause the trigger 4 to become state 1. signal from the output of the trigger 4 allows the passage of signals through the element 2. The good mode of the communication channel is simulated by itself.

The number of pulses from the outputs of the generators 3 and 10 is counted by counters 7 and 8.

The number of pulses from the output of the element And 2 is counted by the counter 6.

Thus, on display unit 9, induction is induced:

11793664

oxen to be transferred; the number of symbols received correctly on the receiving side; the number of pulses inducing the transition of channel 5 to a bad state; as well as the number of pulses inducing the link to a good state.

Claims (1)

DEVICE FOR MODELING COMMUNICATION SYSTEMS, containing a message generator whose output is connected to the first input of the AND element and the information input of the counter of transmitted messages, the output of the And element is connected to the information input * of the counter of correctly received messages, trigger, first generator of a random pulse sequence, counter of correctly received distortion counter, communication channel failure counter, communication channel recovery counter, installation inputs of all counters are combined and are the installation input of the device, and the output The odes of the counters are connected to the corresponding inputs of the display unit, characterized in that, in order to increase the simulation accuracy, it additionally contains a second random pulse generator, the output of which is connected to the information input of the communication channel recovery counter and the first trigger input, the second input of which is connected to the output of the first generator of a random pulse sequence and the information input of the failure counter of the communication channel, the output of the trigger is connected to the second input of the element I. >