SU1256217A2 - Device for forecasting conditions of communication channel - Google Patents

Abstract

The invention relates to telecommunications and is an improvement to the device described in Aut. St. , No. 1195456. The time taken to make decisions about the quality of the communication channel is reduced by changing the thresholds depending on the observed time interval. The device contains a driver of the current evaluation signal, a discriminator 2 zones of evaluation values, a driver of 3 time intervals, a counter 4 (L with NJ 0US. 1

Description

12562

time intervals, switch 5, calculation blocks 6 and 7, blocks 8 and 9, addition, memory blocks 10 and 11, division unit | 12, comparison unit 13, threshold signal sensor 14, reset signal generator 15, display unit 16. The goal is achieved by the introduction of a decoder 17 and a block 18 for changing threshold signals containing a block of decoders, two memory blocks, two multipliers, and a speed sensor

The invention relates to telecommunications, and can be used to predict the quality of a communication channel in the course of its monitoring and is an improvement on the aut. St. No. 1195456.

The purpose of the invention is to reduce the time to decide on the quality of the communication channel by varying the thresholds depending on the observed time interval.

FIG. 1 shows a structural electrical circuit of the device; FIG. 2 shows an embodiment of a block for changing threshold signals.

A device for predicting the state of a communication channel contains (FIG. 1) a driver 1 of the signal

„

taper evaluation, discriminator 2 evaluation value zones, shaper 3 time slots, counter 4 time slots, switch 5, first 6 and second 7 calculation blocks, first 8 and second 9 addition blocks, first 10 and second 11 memory blocks, division block 12 , block 13 comparison, sensor

14th threshold signals, driver

15 reset signals, an indication unit 1o, a decoder 17, a threshold signal measurement unit 18, containing (FIG. 2) a decoder unit 19, the first 20 and second 21 memory blocks, the first 22 and second 23 multiplications, and the speed sensor 24 threshold changes.

The device works as follows.

17

threshold changes. An initial overstatement of thresholds is necessary to meet the requirements for the likelihood of errors of the first and second kinds. Starting with relatively large thresholds and gradually reducing them, the average number of tests can be obtained less than if a small threshold value was used during the whole process, I Cp f-ly, 2 ill.

five

20

to

The essence of the operation of the proposed device is to change the thresholds B depending on time. This is based on the property of a sequential decision procedure, which is that starting from relatively large thresholds and gradually reducing them, you can get an average number of trials less. than if during the whole process a small threshold value was used. At that, the initial overestimation of thresholds is necessary to meet the requirements on the likelihood of errors of the first and second kind.

The implementation of a sequential truncated procedure with varying thresholds in the proposed device is as follows.

Let q, (n) and q (p) be non-increasing and non-decreasing functions of p. Measurements are made as long as a consistent likelihood ratio, (n) is between an O1 ().

and e

 . (P)

li ()

where n 1, (n-1).

When L (n) fog (11) get q L (n) fr q (n)

If L (n) b q, (n), then a decision is made about the good state of the communication channel; if L (n) q (n), then the channel is considered to be healthy; if q (n) L (n) i q, (n), then the process continues.

31256217

The functions q (n) and q (ri) can be represented as

q, (n) s,

(1) s; (1 Co

but

and

I 1 -E where C,,

 The given probabilities of errors of the first and second kind, g and g, characterize the initial steepness of the converging thresholds and determine the speed at which the process approaches to truncation.

The Error signal (Fig. 1) is fed to the inputs of the former 1 current evaluation signal and the discriminator 2 evaluation value zones. Shaper 1 calculates errors during the measurement interval () specified by the shaper of 3 time intervals, classifies the state of the communication channel, producing the current channel quality estimate for the expired pth measurement interval in the binary estimation system (Norm (H), Avari ( A) The discriminator 2 zones of the evaluation values divides the possible number of errors in the time interval Cp, in estimating H (A) and m zones (t 10), with the maximum possible number of errors (in estimating A) and in the absence of errors ( H) is assigned the highest K number, and intermediate zones are assigned K numbers; (m) Counter 4 counts the number of observed time intervals and gives a signal about the number of the time interval to the decoder 17. Closer 5, according to the signals received by it, Norm or Avari provides the signal of the number zones, respectively, to the input of the first computing unit 6 or to the input of the second computing unit 7, where, based on the signal about the zone number K: (1 jm), the total number of zones m and the maximum number. observations, the construction of the increments U Pn (p) or A F (n) of the empirical integral functions of the distribution of the healthy and emergency states of the communication channel is made on the nth observation interval:

.Fjn)., 1 Uvii

four

K;, (n)

to,

 Max

ten

five

2 25 In the first 8 and second 9 blocks of addition, the values of the increments A F, (n) and 4 U (n) are summed with the corresponding values of the empirical integral distribution function calculated for (n-1) time intervals f, F (n- 1) and RD (p-1), which come from the outputs of the first 10 and second 11 memory blocks:

F (n) F (n-l) + 4E „(n) F (n) F, (n-1) + bF (n) ,.

The values F (p) and Fd (p) are fed to the inputs of the block. 12 divisions and za-. writing to the first 10 and second 11 blocks of memory.

The division unit 12 performs the arithmetic division operation:

, (n) 44.

FA (n)

and a log likelihood ratio log 1 (p) L (n) to the input of the comparison unit 13.

Comparison unit 13 is based on comparison of L (n) with threshold signal values q. (p) and q (p), set from the threshold signal change block 18, makes a decision about the predicted state of the communication channel.

The decision rule can be written as follows: for L (n), the decision is Norm; At L (n) q (n), Avariya's decision is made; at qj (n): L (n) q, (n), no decision is made, observations continue in the (n + 1) -th interval (n + 1).

After observing the interval defined by the decoder 17, the signal from the output of the latter enters the comparison unit 13, in which it is compared with the value; threshold C set by the sensor 14 threshold signals.

In this case, the decision rule can be written as follows: for L (njygn.p) 5 C, the decision is made of the Norm; at L (C) Avariya’s decision is made.

The signal from the output of the comparator unit 13 is fed to the driver input.

15 reset signals, from the output of which a signal is sent to reset the counter 4 and to the first 10 and second 11 memory blocks for resetting them.

The unit 18 for changing the threshold signals operates as follows (Fig. 2).

Counter 4 signals the number of the interval to the input of block 19 of decoders, which in turn generates an excitation signal through one of t inputs to the first 20 and second 21 memory blocks, allowing the reading of the coefficients oi; (in the nth column. The signal from the sensor 24 of the threshold measurement speed is fed through one of the m inputs to the first 20 and second 21 memory blocks to select the i-th coefficient from the nth column. Selected in the first 20 and second 21 In the memory blocks, the coefficients k, ' (oi, -) changes in the speed of the thresholds are received respectively at the inputs of the first 22 and second 23 multiplication units, where, multiplied by the values of the thresholds C and C, go to the inputs of the comparison unit 13. The second input of the first (second) 22 (23). Multiplication is intended to receive threshold signals from the sensor 14 Limiting the value of Cd (C,) threshold.

No. 1195456, characterized in that, in order to shorten the time to make decisions about the quality of the communication channel, a decoder was inserted between the output of the time interval counter and the third input of the comparison unit, and between the additional sensor outputs the threshold signals and the fourth and fifth The inputs of the comparison block are 10 threshold signal change blocks, the control input of which is connected to the output of the time counter.

20

25

Claims (2)

1. A device for predicting a 35 channel state by aut. St. f. / J five 2. Devices according to claim 1, characterized in that the block of change of threshold signals is made in the form of a speed sensor for changing thresholds, a block of decoders connected in series to the first memory block, the first inputs of which are connected to the outputs of the block of decoders, and the first multiplication unit connected to the second block of pam, the first inputs of which are connected to the outputs of the decoder unit, and the second multiplication unit, the outputs of the speed sensor for changing thresholds are connected to the second inputs of the first. 30 of the second memory block, the input of the decoder block is the control input of the threshold signal change block, whose inputs and outputs are respectively the second inputs and outputs of the first and second multiplication blocks. Hmea.t A v / j. rv, --id-tTi Mr. W with I. Derbak From fn. H Compiled by E.Golub Tehred I.Popovkch Order 4837/58 Shooting gallery; 1ж 624Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 562176 No. 1195456, characterized in that, in order to shorten the time to make decisions about the quality of the communication channel, a decoder was inserted between the output of the time interval counter and the third input of the comparison unit, and between the additional sensor outputs the threshold signals and the fourth and fifth The inputs of the comparison block are 10 threshold signal change blocks, the control input of which is connected to the output of the time counter. Proofreader L. Patay