RU2623881C1 - Method of increasing information transmission speed at time-pulse modulation - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method of increasing the information transmission speed at time-pulse modulation is accomplished by simultaneous operation of one broadband radio transmitting device by two or more channels with pseudo-random time-pulse modulation. At the reception at one time interval in a single channel, reception is conducted at one frequency, and on the second channel - at the other one.

EFFECT: increasing the information transmission speed with pseudo-random time-pulse modulation.

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Description

The invention relates to the field of radio engineering and communication and can be used in communication systems with an extended spectrum of signals.

It is known that in case of pseudo-random time-pulse modulation (PWIM), information is determined by the time position (delay) of the signal over a fixed time interval in accordance with a special code generated on the basis of a pseudorandom sequence of operating frequencies in a wide frequency band fixed for the duration of information transmission. This method is described in the literature: Barkhota V.A., Gorshkov V.V., Zhuravlev V.I. Communication systems with the expansion of the spectrum of signals. Results of science and technology. Communication M.: VINITI, 1990, v. 5. Borisov V.I., Zinchuk V.M., Limarev A.E. and others. Interference immunity of radio communication systems with the expansion of the spectrum of signals by modulation of the carrier pseudorandom sequence. M .: Radio and communications, 2003. Borisov V.I., Zinchuk V.M., Limarev A.E. Interference immunity of radio communication systems with the expansion of the spectrum of signals by the method of pseudo-random tuning of the operating frequency. M .: Radio-Soft, 2008.

The disadvantage of this method is the relatively low speed of information transfer.

The purpose of the invention is to increase the speed of transmitted information in pseudo-random time-pulse modulation.

This goal is achieved by the simultaneous operation of one broadband radio transmitting device with two or more channels of pseudo-random time-pulse modulation, while receiving at one time interval in one channel, the reception is on one frequency, and on the second channel on the other.

With time-pulse modulation at the reception, the value of the pseudo-random frequency of the transmitted signal is known, but the number of the temporary position is unknown. The delay time from the reference point of the time interval T ₀ to the time of the position during which the signal arrives determines the transmitted information.

The method is implemented as follows. With time-pulse modulation, a certain time interval T ₀ is synchronized at the reception and transmission. This interval is divided into N equal time positions, such that T ₀ = N⋅Δt, where Δt is the duration of one time position.

If the probability of coincidence in time of the radiation pulses specified by each channel is quite small, then it becomes possible to simultaneously operate two or more channels using a single power amplifier. It should be borne in mind that in each of the two channels, the pseudo-random frequency distribution is different and for this reason, reception at one time interval in one channel receives at one frequency, and on the second channel at the other.

Consider the operation of two channels with time-pulse modulation in one time interval. Since noise immunity requires the maximum approximation of the signal in the frequency and time domain to signals of natural origin, we will accept the laws of distribution of pseudorandom values of the frequency and time of pulse emission are equally probable. In this case, the probability of a signal appearing at any one of the positions p {t} is determined by the relation

The appearance of two signals at the same time position can qualify as a product of events No. 1 and No. 2 [Abezgauz G.G., Tron A.P., Kapenkin Yu.N., Korovina I.A. Handbook of probabilistic calculations. M .: Military. published by M.O., 1970], and the probability of such an event is determined by the product of their probabilities. Taking into account possible permutations of events No. 1 and No. 2 (it should be considered as the sum of events), and with a larger number of simultaneously operating communication channels and taking into account their locations [Bronstein I.N., Semendyaev K.A. Math reference. M .: Nauka, 1964], the general formula for calculating the probability of the appearance of two signals at the same time position has the following form:

where Q _i - coincidence events of 2 signals at one time position;

n is the number of simultaneously operating channels under the condition n≤N;

- размещения из n элементов (число одновременно действующих каналов) по 2 (два совпавших на одной временной позиции канала).

- placement of n elements (the number of simultaneously operating channels) in 2 (two coinciding on the same temporary position of the channel).

In FIG. 1 as an example, graphs of changes in the probability p (n), p1 (n) of time coincidences of 2 signals from a different number n simultaneously acting at time-pulse modulation for cases N = 100 and N = 300 and, accordingly, a change in the number of simultaneously working channels from 1 to 100 (p (n)) and from 1 to 300 (p1 (n)).

In FIG. 2 shows the same graphs as in FIG. 1, but only its lower part on a larger scale in order to make it easier to determine the allowable number of simultaneously working communication channels with frequency hopping, given the probability of coincidence in time of the signals from two of them. So, a probability level of 0.01 corresponds to a permissible value of simultaneously operating channels equal to 9 at 100 temporary positions and 30 at 300 temporary positions. With a probability level of 0.001-4 channels and 10 channels, respectively.

This result allows us to conclude that it is possible in principle to increase the speed of information transfer during time-pulse modulation due to the simultaneous operation of several channels of this type with a given probability of superposition of radiation pulses.

Claims (1)

A method of increasing the speed of information transmission in time-pulse modulation, which is carried out by simultaneous operation of one broadband radio transmitting device with two or more channels with pseudo-random time-pulse modulation, while receiving at one time interval in one channel, receiving at the same frequency, and at the second channel - at a different frequency.

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