RU2519041C2 - Method for pulse interference control based on localisation thereof using min-max threshold in adaptive radio signal receiving systems - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to adaptive filtering. For a received observation signal, which is an additive mixture of a useful signal, noise and pulse interference, localisation and reduction of the effect of the pulse interference is achieved by forming an observation signal envelope, breaking down said signal envelope into L/N units (L is the length of the original observation signal, N is the size of the unit, where L is a multiple of N), selecting the maximum value of the envelope at each unit and forming a first sequence therefrom; using the obtained first sequence to form units of length M (L/N being a multiple of M), selecting the minimum value in each unit and forming a second sequence therefrom; further, using a cubic interpolation technique to plot a curve, where the L/N·M of interpolation node points, spaced apart by M·N, used are values of the second sequence, and the boundary node points used are the first and last values of the second sequence; the obtained curve is used as an estimate of the envelope of the useful signal and noise for calculating a min-max threshold, which takes into account the pulse interference detection error probability; the calculated min-max threshold is used to determine the intervals of influence (indices of initial positions, durations) of pulse interference in the original observation signal; when processing the observation signal on the interval of influence of each pulse interference, stopping and determining the state of the algorithm for calculating weight coefficients of adaptive channel distortion correctors or adaptive antenna systems; at the end of the interval of influence of pulse interference, launching the algorithm for calculating weight coefficients of adaptive channel distortion correctors or adaptive antenna systems.

EFFECT: pulse interference control procedure based on localisation thereof using a min-max threshold, reducing the negative impact of pulse interference on adaptive radio signal receiving systems, thereby improving quality of reception.

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Description

The invention relates to the field of adaptive filtering, in particular to systems for receiving radio signals in which methods of combating impulse noise (IP) are used. It can be used to improve the quality of reception of radio signals by eliminating the negative impact of IP on the work of adaptive channel distortion correctors (AK) and adaptive antenna systems (AAS).

One of the factors negatively affecting the quality of radio signals reception is the presence of external IPs in the reception band [3]. They have a random duration, spectral width, and energy, which significantly complicates the fight with them [1, 2, 4-6, 8, 9, 12-14].

A known method of dealing with IP, based on the use of a compensation path, upset with respect to the frequency of the received signal. The disadvantages of the method is the difficulty of forming a copy of the IP in the compensation path and evaluating its parameters, which significantly reduces the effectiveness of compensation.

There are also known methods of dealing with IP, which are based on protecting the input of the demodulator from their effects by limiting the amplitude of the observation signal, locking the input of the decision circuit on the interval of the IP or replacing the observation signal on the IP interval with a noise implementation (or other auxiliary signals). The disadvantage of the first method is the nonlinear distortion of the received signal, the disadvantage of the second is the loss of information transmitted over the interval of the IP.

Known methods of linear filtering IP. The disadvantage is the smoothing of the signal fronts and, as a result, a decrease in reception quality. Median filtering methods are used to suppress PI. They are characterized by two main advantages - good suppression of IP with a duration of less than half the window size of the median filter. The disadvantages include nonlinear transformations of the received signal, leading to distortion of information [11].

The aim of the invention is to reduce the influence of IP on the operation of AK or AAS and to improve the quality of reception of radio signals under the influence of IP.

The basis of the invention is the idea of reducing the impact of IP on the operation of AK or AAS. Reducing the effect is achieved by stopping the adaptation algorithm and fixing its state for the duration of the IP. In this case, the IP can lead to erroneous decisions, but does not violate the adaptive algorithm for calculating the weight coefficients of AK or AAS. To evaluate the time intervals of the IP, a procedure for their localization using the min-max threshold is proposed. The procedure allows you to determine the intervals of the IP and evaluate the envelope of the useful signal and noise against the background of the IP.

To achieve the objective of the invention, a method for controlling impulse noise based on their localization using the min-max threshold in adaptive radio signal reception systems is proposed, in which an envelope of the observation signal is formed to localize the IP, it is divided into L / N blocks (L is the length of the initial observation signal , N is the block size, when L is a multiple of N), select the maximum envelope value on each block and form the first sequence from them; then, blocks of length M are formed from the obtained first sequence (with L / N multiple of M), a minimum value is selected in each block and a second sequence is formed from them; then, using a cubic interpolation method, a curve is constructed where the values of the second sequence are used as ^L / _{N · M} nodal interpolation points located with a step of M · N, and the first and last values of the second sequence are selected as boundary nodal points; the obtained curve is used as an estimate of the envelope of the useful signal and noise for calculating the min-max threshold, taking into account the probability of detection error of SP; the calculated min-max threshold is used to determine the intervals of action (indices of the initial positions, durations) of the PI in the initial observation signal; when processing the observation signal at the interval of each of the IPs, they stop and record the state of the algorithm for calculating the weight coefficients of adaptive channel distortion correctors or adaptive antenna systems; at the end of the interval of action of IP start the algorithm for calculating the weight coefficients of AK or AAS.

The proposed technical solutions can reduce the impact of IP on the operation of algorithms for calculating the weight coefficients of AK and AAS, improve the quality of received signals compared to known methods of dealing with IP [1, 2, 4-6, 8, 9, 12-14].

The invention is illustrated in the drawing (figure 1). The drawing (Fig. 1) shows a device for controlling IP based on their localization using the min-max threshold in adaptive radio signal reception systems.

A device for controlling IP based on their localization (FIG. 1), contains: node 1 — node for generating the envelope of the observation signal; node 2 is a node for dividing the envelope of the observation signal into L / N blocks of length N samples; node 3 is a node for selecting maximum values on each of the L / N blocks and forming the first sequence; node 4 - node splitting the first sequence into L / (N · M) blocks of duration M samples; node 5 is a node for selecting minimum values on each of the L / (N · M) blocks and forming a second sequence from them; node 6 - node cubic spline interpolation based on the second sequence and the calculation of the min-max threshold; node 7 is a node comparing the envelope of the received observation signal with a min-max threshold; node 8 - AK or AAS.

t=0,1…L-1 исходный сигнал наблюдения длительностью L отсчетов, представляющий собой аддитивную смесь полезного сигнала s_t, шумов и импульсных помех,

t=0,1…L-1.Let be

t = 0.1 ... L-1 the initial observation signal with a duration of L samples, which is an additive mixture of the useful signal s _t , noise and impulse noise,

t = 0.1 ... L-1.

The node 1 is designed to receive samples Y _{t the} envelope of the observation signal

Where

t = 0.1 ... L-1,

re (y _t ), im (y _t ) - operations to extract the real and imaginary parts of the original observation signal.

At node 2, the envelope of the observation signal Y _t

t = 0,1 ... L-1 on L / N blocks of length N samples each:

Y _{j, i} , j = 0.1 ... L / N-1, i = 0.1 ... N-1, where j is the block number, i is the reference number of the envelope of the observation signal in the block.

в каждом из L/N блоков и формирование из этих значений первой последовательности Y^max:In node 3, the maximum value of the envelope of the observation signal is selected

in each of the L / N blocks and the formation of these values of the first sequence Y ^max :

, j=0,1…L/N-1, i=0,1…N-1.

, j = 0.1 ... L / N-1, i = 0.1 ... N-1.

In node 4, the first sequence Y ^max is divided into L / (N · M) blocks of length M samples each:

where k is the block number, q is the reference number of the sequence Y ^max in the block.

в каждом из Node 5 selects the minimum value

in each of

и формирование из этих значений второй последовательности Y^min,max.L / (N · M) blocks of the first sequence

and the formation of these values of the second sequence Y ^{min, max} .

, k=0,1…L/(N·M)-1 второй последовательности Y^min,max, а в качестве граничных узловых точек выбирают первое

и последнее At node 6, cubic spline interpolation generates an estimate of the envelope of the useful signal and noise S _t in each k block. As the nodal interpolation points located through M · N samples, use the values

, k = 0.1 ... L / (N · M) -1 of the second sequence Y ^{min, max} , and as the boundary nodal points choose the first

and last

значения второй последовательности; полученную кривую используют в качестве порога.

values of the second sequence; the resulting curve is used as a threshold.

- оценка огибающей полезного сигнала и шума на k блоке, где

- estimate of the envelope of the useful signal and noise on the k block, where

t∈ [k · N · M, (k + 1) · N · M], k = 0.1 ... L / (N · M) -1;

,

- значение функции и производные в узловых точках [7, 10].a _k , b _k , c _k - spline coefficients for the k-block, S _{k, t} = a _k ,

,

- the value of the function and derivatives at the nodal points [7, 10].

на всем интервале наблюдения обозначим S_t, t=0,1…L-1.The union of the estimates S _{k, t} , t∈ [k · N · M, (k + 1) · N · M],

over the entire observation interval we denote S _t , t = 0.1 ... L-1.

The node 7 compares the estimates of the envelope of the observation signal Y _t with the calculated min-max threshold Р _t = S _t + Δ (Р _Ош ), where

t = 0.1 ... L-1,

Δ (P _Osh ) is the bias of the estimate S _t , for a given probability of detection error of SP.

If the min-max threshold is exceeded, a decision is made to detect the IP and the interval of its action is determined (index of the initial position Idx, duration Δt).

, где

where

t = 0.1 ... L-1,

k∈ [0, L-1],

Δt = Idx _m -Idx ₀ , the duration Δt is the difference between the indices m - the last and 0 - the first count of the IP, when the min-max threshold is exceeded.

The node 8 processes the observation signal y _t , on the interval of each of the IPs (Idx, Δt), stops and fixes the state of the algorithm for calculating the weight coefficients of AK or AAS; at the end of the interval, the IP starts the algorithm for calculating the weight coefficients of AK or AAS. At the output of the node, an estimate of the useful signal S _{t is formed} .

The implementation of the described method can be hardware, software or hardware-software.

Achievable technical result of the proposed method is the above-described procedure for controlling IP, based on their localization using the min-max threshold, reducing the negative impact of IP on the work of adaptive radio signal reception systems and, as a result, improving reception quality.

Information sources

1. Venskauskas K.K., Malakhov L.M. Impulse noise and their effect on the communication system. - Foreign Radio Electronics, 1977, No. 5, p.3.

2. Vasiliev K.K., Glushkov V.A., Dormidontov A.V., Nesterenko A.G. Theory of electrical communications: textbook / under the total. ed. K.K. Vasilyeva. - Ulyanovsk: UlSTU, 2008 .-- 452 p.

3. Venskauskas K.K., Malakhov L.M. Impulse noise and their impact on radio communication systems (review). - Foreign Radio Electronics, 1978, No. 1, pp. 95-125.

4. Korzhik V.I., Fink L.M., Schelkunov N.N. Calculation of noise immunity of discrete message transmission systems: Handbook / Korzhik V.I., Fink L.M., Schelkunov K.N .: Ed. L.M. Finca. - Radio and Communication, 1981. - 232 p.

5. Kuzmin B.I. Impulse noise and noise immunity analysis (review). - Izv. universities. Radio Electronics, 1981, t.24, No. 4, p. 4-16. Ivankin P.A., Lebedinsky E.V. On the mathematical model of random station interference in radio communication systems. - Radio engineering, 1983, t. 38, No. 6, p. 47-50.

6. Komarovich A.F., Sosunov V.N. Random interference and reliable KB communication. - M.: Communication, 1977 .-- 136 p.

7. Kostomarov D.P., Taborsky A.P. Introductory lectures on numerical methods.

8. Protsenko L.D. Mathematical models of impulse noise. - Izv. universities. Radio Electronics, 1983, v. 26, No. 4, p. 68-73.

9. Remizov L.T. Models of radio interference of natural origin (review). - Radio engineering and electronics, 1981, t.26, No. 2, s.211-237.

10. Rogers D., Adams J. Mathematical foundations of computer graphics. - M .: Mir, 2001. - ISBN 5-03-002143-4.

11. Safronov S.V. Adaptive noise analysis in measuring channels with threshold selection: Thesis for the degree of candidate of technical sciences Joint venture - LETI, 2008, - 173 p.

12. Boner F. Vehicular Radio Frequency Interference - Accomplishment and challenge. - "IEEE Transactions on vehicular Technology" v. VT-16, 1967, p. 58-68.

13. Hall H.M. A new model for "impulsive" phenomena: application to atmospheric noise communication channels. Techn. Report N 3412-8 and 7050-7, August, 1966, Radioscience Lab. Stanford Electronics Labs.

14. Southwick R.A., Schulz R.B. A Method to evaluate the degradation effects of Impulsive Interference. - IEEE International Conference on Communications, Mineapolis, 1974, p. 26C-1-26C-5.

Claims (1)

A method of controlling impulse noise (IP) based on their localization using the min-max threshold in adaptive radio signal reception systems, characterized in that for the localization of the IP they form the envelope of the observation signal, divide it into L / N blocks (L is the length of the initial observation signal , N is the block size, when L is a multiple of N), the maximum value of the envelope on each block is selected and the first sequence is formed from them; then, blocks of length M are formed from the obtained first sequence (when L / N is a multiple of M), a minimum value is selected in each block and a second sequence is formed from them; then, using a cubic interpolation method, a curve is constructed where the values of the second sequence are used in ^L / _{N · M} nodal interpolation points located with a step of M · N, and the first and last values of the second sequence are selected as boundary nodal points; the obtained curve is used as an estimate of the envelope of the useful signal and noise for calculating the min-max threshold, taking into account the probability of detection error of SP; the calculated min-max threshold is used to determine the IP action intervals from their indices of initial positions and durations in the initial observation signal; when processing the observation signal at the interval of each of the IPs, they stop and record the state of the algorithm for calculating the weight coefficients of adaptive channel distortion correctors or adaptive antenna systems; at the end of the IP interval, they start the algorithm for calculating the weight coefficients of adaptive channel distortion correctors or adaptive antenna systems.

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