RU2629012C1 - Method of processing compound signals working in common frequency band - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method of processing compound signals operating in the common frequency band is based on the method of successive approximations and uses the property of such signals - their different levels. At the first stage of the iteration, a more powerful signal is demodulated, it is corrected on the results of noise-immune decoding, the signal is remodulated and subtracted from the total signal, as a result an improved low-power signal is obtained. A second iteration is carried out over a low-power signal, i.e. operations similar to the first iteration are performed.

EFFECT: ability to work on any signals operating in a common frequency band, and the ability to obtain the required quality of information during processing due to consecutive iterations over the signal.

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Description

The invention relates to the field of radio engineering and can be used to process composite signals operating in a common frequency band.

The constant desire for technical closure of information and an increase in the amount of information transmitted in the allotted frequency band led to the use of multi-level phase types of modulation of different multiplicities FM2, FM4, FM8, KAM16, KAM32, KAM64, KAM128, KAM256, when doubling the manipulation factor doubles the increase in throughput also double ([1] Spilker J. Digital satellite communications. Translated from English. Edited by VV Markov. M: Communication, 1979).

Currently, another method is proposed for the technical closure of information and at the same time double the capacity of information transmission systems in the allocated frequency band - this is a method of compressing signals in the common frequency band, called “Double Talk” and “Carrier-in-Carrier” ([2 ] - Double Talk Carrier-in-Carrier, Bandwidth Compression Providinq Siqnificant Improvements in Sattelite Bandwidth Utilization, September 27, 2004, © 2004 Comtech EF Data Corporation), taken as a prototype.

The processing of such signals is extremely difficult due to the specifics of the formation of the group spectrum.

The essence of the way to double the bandwidth and process such signals [2] is as follows: the frequency band ΔF is allocated to the outgoing subscriber. The connection with the incoming subscriber is carried out in a typical mode, but the same frequency band is allocated to it as the outgoing subscriber, i.e. they operate in a common frequency band on the same carrier. Separation of signals at the transmitting and receiving sides is carried out as follows: the incoming and outgoing stations receive the total signal, each station delays its own signal for the duration of its passage: the subscriber-repeater-subscriber and coherently subtract the “own” signal from the total signal, as a result of which receive a duplex subscriber signal. At the same time, both subscribers of communication systems of the “Spade” type and subscribers combined in group streams of various levels of hierarchical compression can work in the common frequency band. In addition to increasing throughput, this method of organizing communication provides a high degree of technical closure of information, since without extracting one of the signals, it is impossible to obtain information from another (duplex) signal.

It is possible to use a method of processing such signals by the method of receiving one “own” signal in one side station zone of one of the stations (incoming or outgoing stations) and receiving the total signal by another station and subsequent processing, as in the prototype.

However, this method has a number of disadvantages:

- the need for two complex receiving and processing stations;

- the difficulty of delivery, and often the inability to deliver the station to the side lobe of one of the monitored stations;

- the ability to control only one station.

The disadvantage of the prototype method is the inability to process composite signals operating in the common frequency band, due to the lack of access to the "own" signal of the incoming or outgoing stations.

The task to which the proposed method is directed is to simplify the processing of composite signals operating in a common frequency band and expand its functionality.

A characteristic feature of signals operating in a common frequency band is their different levels. The difference in levels varies between 1-3 and more dB, which allows us to solve the problem.

To solve the problem, a method for processing composite signals operating in a common frequency band by the method of successive approximations, in which the total signal is received, is coherently subtracted from the total signal “own” signal, in which a more powerful signal is additionally demodulated to obtain “own” signal, noise-resistant decoding (PUD) with measuring the number of errors; according to the results of the PUD, errors in the information and verification parts of the demodulated signal are corrected, and the received Igna, who further assigned the index "a" is subtracted from the total signal, delayed by performing demodulation time, PUD, error correction, resulting remodeling "their" signals and receive low-power signal. Next, the low-power signal is demodulated, the PUD with error measurement, according to the PUD results, errors in the information and verification parts of the demodulated low-power signal are corrected, the low-power signal is remodulated, the resulting low-power signal and the error correction are subtracted from the total signal delayed for the duration of the demodulation operations, the PUD is corrected, the error correction receive an improved powerful signal. Next, an improved, more powerful signal is demodulated, noise-correcting decoding is carried out with the measurement of the number of errors, according to the results of the PUD, they correct errors in the information and verification parts of the demodulated signal, they remodulate the received signal, and they are subtracted from the total signal delayed for the duration of the demodulation, PUD, error correction, remodulation received an improved powerful signal and receive an improved low-power signal. Next, an improved low-power signal, a PUD with error measurement, and so on are demodulated. There can be several such iterations. After each iteration, according to the results of measuring the number of errors after the PUD, a decision is made to stop or continue iteration operations on the signal. If the number of errors meets the quality requirement of the received signal, the iteration process is terminated. Usually, one to two iterations over the signal are sufficient to obtain the required signal quality.

The technical result is the ability to work on any signals operating in a common frequency band, and the ability to obtain the required quality of information during processing due to successive iterations over the signal.

The combination of distinctive features and properties of the proposed method from the literature are unknown, therefore, it meets the criteria of novelty and inventive step.

In FIG. 1 shows the sequence of operations on the signal according to the proposed method, and in FIG. 2 is a functional diagram of an iterative cell, providing the construction of equipment according to the proposed method.

According to the proposed method (Fig. 1), the following sequence of operations is performed:

- take the total signal is 1;

- demodulate a more powerful signal - 2,

- carry out noise-free decoding (PUD) with measuring the number of errors in the information part - 3;

- according to the results of operation 3 correct errors in the information and verification parts of the demodulated powerful signal - 4;

- remodulate the received signal 5, which is then assigned the index "own" - 5,

- delay the total signal by the delay line 7 for the duration of operations 1-5 and subtract from the total signal the received "own" signal and receive an improved low-power signal - 6;

- demodulate a low-power signal - 8;

- PUD with measuring the number of errors - 9;

- according to the results of operation 9 correct errors in the information and verification parts of the demodulated low-power signal - 10;

- remodulate a low-power signal - 11;

- delay the total signal by delay lines 7, 13 for the duration of operations 1-6, 8-11 and subtract from the total signal received in operation 1, the received low-power signal from operation 11 and receive an improved powerful signal - 12;

- demodulate an improved more powerful signal - 14;

- carry out noise-free decoding of the improved more powerful signal with the measurement of the number of errors - 15;

- according to the results of operation 15 correct errors in the information and verification parts of the demodulated improved powerful signal - 16;

- remodulate the received more powerful signal - 17;

- delay the total signal by delay lines 7, 13, 19 for the duration of operations 1-6, 8-12, 14-17 and subtract from the total signal received in operation 1, the received improved more powerful signal, and receive an improved low-power signal - 18 ;

- demodulate the improved low-power signal - 20;

- PUD with measuring the number of errors - 21.

There can be several such iterations. After each iteration, according to the results of measuring the number of errors after the PUD, a decision is made to terminate or continue iteration operations on the signal according to the quality of the information received. As soon as the number of errors meets the quality requirement of the received signal, the iteration process is terminated. Usually, one to two iterations over the signal are sufficient to obtain the required signal quality.

The invention consists in the following.

Let the system use two-phase modulation. Then (see Fig. 1), the low-power signal S2 is the noise for the more powerful signal S1. If the signal-to-noise ratio is more than 1-2 dB, then signal S1 is demodulated - 2, provide noise-free decoding - 3 with measurement of the number of errors. If the probability of errors is less than the permissible norm, then the information is removed after the PUD - 3, if the probability of errors is greater than the threshold, then according to the results of operation 3, errors are corrected - 4 in the information and verification parts in the demodulated signal, then the signal is modulated - 5. As a result, they receive improved in terms of the number of errors more powerful signal S1. Now subtract from the total signal - 1, delayed by the delay line - 7 for the duration of operations 2, 3, 4, 5, the received remodulated signal S1 and get the improved low-power signal S2 - 6. This completes the first iteration over the signal

Next, a second iteration is performed on the signal (operations 8, 9, 10, 11, 12), then a third iteration (operations 14, 15, 16, 17, 18,), etc.

At each stage of iterations, the probability of errors after the PUD is measured, and if the number of errors corresponds to the permissible norm, then after this operation the PUD is allowed to retrieve information.

Usually, one to two iterations over the signal are sufficient to obtain the required signal quality.

The equipment according to the proposed method can be implemented on a typical iterative cell (Fig. 2), which contains a series-connected demodulator 1, a noiseless decoder (PUD) 2, an error corrector 3, a remodulator 4, an adaptive equalizer 5, an adder 6, and the second input of the corrector Error 3 is connected to the output of demodulator 1, the output of remodulator 4 is connected to the second input of the adder 6, and the second input of the adaptive equalizer 5 through the delay line 7 is connected to the input of demodulator 1.

The iteration cell works as follows.

Let a total signal be received in which one signal is larger than the other (S1> S2). Then the signal S2 can be considered as noise with respect to the signal S1.

A signal of a higher level S1 is demodulated in demodulator 1, errors in the information part are corrected in the PDU 2 and the probability of errors in the signal is measured after the PDU 2. If the probability of error is normal, the information after the PDU 2 is the information output of a more powerful signal S1, if the probability of error below normal, then according to the results of noise-free decoding in the PUD 2 in error corrector 3, errors in the information and verification parts of the signal are corrected without propagating errors. Next, the signal is modulated in remodulator 4 using the reconstructed carrier from demodulator 1. In adaptive equalizer 5, the signals from remodulator 4 and the total signal S1 + S2 delayed in the delay line 7 are aligned in level and phase, and then the signal after the modulator is subtracted from the total signal in adder 6 4. The resulting improved low-power signal S2 is supplied to the next iteration cell.

Claims (1)

A method for processing composite signals operating in a common frequency band in which a total signal is received is coherently subtracted from the total signal “own” signal, characterized in that in order to obtain “own” signal, a more powerful signal is additionally demodulated, error-correcting decoding is performed with measurement of the number of errors , according to the results of noise-free decoding, errors in the information and verification parts of the demodulated powerful signal are corrected, the received signal is remodulated, which is then assigned they build the “own” index, subtract from the total signal delayed for the duration of the demodulation, error-correcting decoding, error correction, remodulation operations, receive the “own” signal and receive a low-power signal, demodulate a low-power signal, perform noise-resistant decoding with measurement of the number of errors, according to the results error-correcting decoding correct errors in the information and verification parts of the demodulated low-power signal, remodel the low-power signal, subtract from the total signal delayed during demodulation, error-correcting error correction decoding, remodulation, received low-power signal and receive an improved powerful signal, demodulate an improved more powerful signal, perform noise-resistant decoding of an improved more powerful signal with the measurement of the number of errors, correct errors according to the results of error-correcting decoding in the information and verification parts of the demodulated improved powerful signal, remodulate the received bol e powerful signal is subtracted from the total signal delayed for the duration of the demodulation, error-correcting decoding, error correction, remodulation operations, the received improved more powerful signal and receive the improved low-power signal, demodulate the improved low-power signal, perform noise-resistant decoding with measurement of the number of errors, after each iterations according to the results of measuring the number of errors after error-correcting decoding decide on the termination or continuation of operations teratsii on the signal quality information received.

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