RU2752790C1 - Method and apparatus for multi-channel reception and transmission of optical signals based on forming sector directivity patterns and azimuth tracking system - Google Patents

Abstract

FIELD: communication equipment.

SUBSTANCE: invention relates to optical communication equipment and can be used as part of multi-channel mobile systems for wireless information transmission by means of ultraviolet radiation. To realise the described result, a sector directivity pattern of the reception and transmission module of the multi-channel mobile wireless optical communication system is formed at mobile and stationary subscriber sites of the network. The apparatus constitutes a structure of a reception and transmission module made in the form of a spherical sector containing at least one lower tier with M faces located at different angles to the vertical, with cells for accommodation of M optical transmitters providing a sector directivity pattern for propagation of transmitted light rays in the required range of angles by azimuth; at least one upper tier with N faces at the base, also located at different angles to the vertical and containing cells for accommodation of N optical receivers. The position of the reception and transmission module is adjusted by azimuth using an azimuth tracking system by the maximum of the effective signal, including a direction finding apparatus, a low-pass filter (LPF), and an actuator.

EFFECT: reducing equipment costs by reducing the amount of channels for transmission and reception of optical signals while maintaining the reliability and distance of communication in the mode of absence of direct visibility between subscribers of the network during movement and rotation of mobile communication nodes.

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Description

The invention relates to the field of optoelectronic systems and can be used in laser (optical) communication systems with a dynamic structure, including when using optical communication channels in networks with mobile subscriber stations.

A known method of organizing access to a network for transmitting data packets is based on direct restructuring of the radiation beam of a laser transmitting device in the direction of the corresponding receiving device. The disadvantage of this method is the complexity of alignment and, accordingly, the possibility of losing part of the transmitted information by subscribers (receiving devices) due to the misalignment of the orientation of the receiving and transmitting optical antennas (especially in the mobile communication line) [RF Patent No. 21977783, Russia, published 03/27/2003].

Also known is a method for multichannel transmission of optical signals using duplication of the main optical channel with additional optical channels [RF Patent No. 2459271, Pub. 20.08.2012]. In this method, the laser receivers are installed at a distance with the location to the side relative to the considered axis of propagation of the radiation beam of the transmitting laser means. In this case, the receiving devices receive the radiation scattered by the atmosphere from the transmitting laser device. For this purpose, the receiving antennas of the laser receiving devices are oriented in the direction of the beam axis of the transmitting laser device, and the information transmitted by the laser transmitting device is extracted by each of the laser receiving devices according to the change in the amplitude of the leading and trailing edges of the output pulse of the photodetector. The stability of information transmission to several subscribers is carried out due to the duplication of the main optical channel with additional channels that are less critical to the orientation of the directional patterns of optical antennas. In this case, in the method of multichannel transmission of optical signals based on aiming the radiation flux of the laser transmitter in the direction of one of the N laser receivers, N-1 laser receivers are additionally installed at a distance with the location to the side relative to the considered axis of propagation of the radiation beam of the transmitting laser means. In this case, the width of the radiation pattern of the receiving device is much wider than the duration of the transmitted pulse and the diameter of the section of the laser beam, which allows them to receive radiation from the transmitting laser device scattered by the atmosphere. The receiving antennas of the N-1 laser receiving devices are oriented in the direction of the beam axis of the transmitting laser device, and the information transmitted by the laser transmitting device is extracted by each of the N-1 laser receiving devices by changing the amplitude of the leading and trailing edges of the output pulse of the photodetector.

The disadvantage of this method is the impossibility of stable transmission of information in the case of mobile communication systems, when the receiving device is moved to the side relative to the direction of propagation of the optical radiation of the transmitting device. In addition, a loss of communication is possible due to the loss (absence) of a direct optical channel between the transmitter and the receiver. This is typical for mobile networks with a dynamic structure. In addition, when an object moves in mobile communication networks with a single emitting LED with a narrow scattering angle, reception becomes almost impossible.

The closest in technical essence and the achieved result (prototype) is a method of multichannel transmission of optical signals and a device for its implementation [RF Patent No. 2719548, Pub. 04/21/2020]. In this method, at the mobile and stationary subscriber stations of the network, a circular radiation pattern of the transceiver module of the multichannel mobile wireless optical communication system is formed. The presence of several optical transmission and reception channels with a circular arrangement of optical transmitters and receivers allows to ensure reliable communication in the absence of line of sight between network subscribers when moving and turning mobile communication nodes, as well as to increase its range and sensitivity of receiving channels by narrowing the radiation angles of optical transmitters and angles of view of optical receivers. To ensure reliable communication between network subscribers when moving and turning mobile communication nodes, the required number of transmitters and receivers is determined from the conditions of full azimuth coverage. The specified method consists in aiming the radiation flux from the N _T optical transmitting device in the direction of one of the N _R optical receiving devices installed in accordance with a circular arrangement, the number of which is selected based on the conditions of full coverage in azimuth in accordance with the expression

where φ _{T, R} is the width of the directional pattern of the optical transmitting and optical receiving device, and the elevation angles of the optical transmitting and optical receiving device are selected from the conditions for avoiding terrain obstacles to ensure communication in the absence of line of sight. A variant of the device that implements this method of wireless transmission of information by means of ultraviolet radiation is the design of the transceiver module, which is close to hemispherical, which in cross section is a multi-tiered truncated pyramid. This beamforming device is characterized by the use of several lower tiers of the structure, located at small and large elevation angles to the horizontal and having several edges at the base for placing optical transmitters in them, providing a circular radiation pattern for the propagation of transmitted light rays; as well as the use of several upper tiers of the structure, which are also located at small and large elevation angles to the horizontal and have several edges at the base for placing optical receivers in them, providing a circular radiation pattern for omnidirectional reception of transmitted light beams.

The disadvantage of this method and the device that implements it is the high hardware costs associated with the need to create a pie chart of transmitters and a pie chart of receivers. This drawback is especially critical for optical communication devices in the UV-C range from 200 nm to 280 nm, requiring the use of rare and expensive optical components.

The task of the group of inventions is aimed at eliminating the shortcomings of the prototype.

The technical result of the invention is to reduce the number of channels for transmitting and receiving optical signals while maintaining the reliability and communication range in the absence of line of sight between network subscribers when moving and turning mobile communication nodes, which reduces hardware costs.

The technical result is achieved due to the fact that at the mobile and stationary subscriber stations of the network, the formation of the sector radiation pattern of the transceiver module of the multichannel mobile wireless optical communication system is performed. The presence of several optical transmission and reception channels with a sectoral arrangement of optical transmitters and receivers makes it possible to ensure reliable communication in the absence of line of sight between network subscribers when moving and turning mobile communication nodes, while maintaining its range and sensitivity of receiving channels by narrowing the radiation angles of optical transmitters and angles of view of optical receivers (Fig. 1). Adjustment of the position of the transceiver module in azimuth is carried out using a goniometric tracking system for the maximum of the useful signal (Fig. 2).

The proposed method for multichannel reception and transmission of optical signals, including aiming the radiation flux N _{T of the} optical transmitter in the direction of one of the N _R optical receiver, contains the following new features:

- set N _T optical transmitting devices and N _R optical receiving devices in accordance with the sectoral arrangement in the horizontal projection of the channel along the sector of the circle to form a sector radiation pattern of the receiving-transmitting module of a multichannel mobile wireless optical communication system, and the number of optical devices is selected in accordance with the expression

N _{T, R} = Δθ _{T, R} / φ _{T, R} , (1)

where Δθ _{T, R} is the range of azimuthal angles of the set of optical transmitting and optical receiving devices, φ _{T, R} is the width of the radiation pattern of the optical transmitting and optical receiving device;

- adjustment of the position of the receiving-transmitting module in azimuth is carried out using a goniometric tracking system for the maximum of the useful signal in the direction finding device, which generates a signal characterizing the deviation of the signal source (IS) from the equisignal direction (RSN) for which the input radiation is fed to the sun-blind filter , where blocking of side solar radiation is carried out, then the useful signal is fed to the input of the optical receiver and amplified in the amplifier, then the generated signal is filtered in a low-pass filter and sent to the actuator to compensate for the azimuthal deviation of the IC from the PCH.

To implement the claimed method, a device for multichannel transmission of optical signals is proposed, which is a design of a transceiver module made in the form of a spherical sector containing at least one lower tier having M faces located at different angles to the vertical with cells for placing M optical optical transmitting devices providing a sector radiation pattern for the propagation of transmitted light beams in the required range of angles in azimuth, at least one upper tier having N edges at the base, also located at different angles to the vertical and containing cells for placing N optical transmitting devices in them, in this case, the azimuth adjustment of the position of the transceiver module is carried out using a goniometric tracking system for the maximum of the useful signal, including a direction finding device, a low-pass filter (LPF) and an actuator.

In this case, the number N _T optical transmitting devices and N _R optical receiving devices are selected in accordance with the expression according to the formula (1)

Compensation for azimuthal deviation of the signal source from the equal-signal direction is carried out using a goniometric tracking system for the maximum of the useful signal, containing a direction finding device, a low-pass filter (LPF) and an actuator. The direction finding device includes a sun-blind filter, an optical receiver and an amplifier.

The invention is characterized by the following graphical representations.

Fig. 1 - vertical xOy and horizontal xOz projections of the channel in the non-line-of-sight mode with the sectoral arrangement of optical transmitters and receivers.

Fig. 2 - Diagram of the goniometric tracking system for the maximum of the useful signal.

Fig. 3 is an image of a transceiver module for multichannel mobile wireless ultraviolet communication systems that implements the inventive method.

– передающий модуль,

– приемный модуль,

– расстояние между передающим и приемным модулями,

,

, ψ_T,R – угол места, ширина диаграммы направленности и азимут соответственно, индекс T относится к передатчику, индекс R – к приемнику,

– угол рассеяния,

– общий объем диаграмм направленности передатчика и приемника,

– расстояние от передатчика и приемника до центра области V, r_T,R - расстояние от препятствия до передатчика и приемника соответственно. Отдельные оптические передатчики передающего модуля S₁… S_NT и отдельные оптические приемники приемного модуля R₁… R_NR расположены в горизонтальной проекции канала по сектору окружности и показаны точками (не в масштабе, расстояния между любыми отдельными передатчиками и любыми отдельными приемниками <<r). Для обеспечения надежной связи между абонентами сети при перемещениях и поворотах мобильных узлов связи необходимое число передатчиков N_T и необходимое число приемников N_R определяют из условий полного покрытия сектора с требуемой шириной по азимуту Δθ_T,R: , по формуле (1)FIG. 1 shows the vertical xOy and horizontal xOz projections of the channel in the non-line-of-sight mode with the sectoral arrangement of optical transmitters and receivers. Where

- transmitting module,

- receiving module,

- the distance between the transmitting and receiving modules,

,

, ψ _{T, R} - elevation angle, beam width and azimuth, respectively, index T refers to the transmitter, index R - to the receiver,

- scattering angle,

- the total volume of the radiation patterns of the transmitter and receiver,

Is the distance from the transmitter and receiver to the center of the region V, r _{T, R} is the distance from the obstacle to the transmitter and receiver, respectively. The individual optical transmitters of the S ₁ ... S _NT transmitter module and the individual optical receivers of the R ₁ ... R _NR receiver module are located in the horizontal projection of the channel along a sector of the circle and are shown by dots (not to scale, distances between any individual transmitters and any individual receivers << r) ... To ensure reliable communication between network subscribers when moving and turning mobile communication nodes, the required number of transmitters N _T and the required number of receivers N _{R are} determined from the conditions of full coverage of the sector with the required width in azimuth Δθ _{T, R} :, according to the formula (1)

The diagram of the goniometric tracking system for the maximum of the useful signal for adjusting the position of the transceiver module in azimuth is shown in Fig. 2. It consists of a direction-finding device, a low-pass filter (LPF) and an actuator.

The direction finding device generates a signal characterizing the deviation of the signal source (IS) from the equisignal direction (RCH) as follows: the input radiation passes through a sun-blind filter that blocks the incident solar radiation and transmits the useful signal. The signal from the output of the sun-blind filter is fed to the input of an optical receiver (OPRM), which is a photodiode, an array of photodiodes or a photomultiplier tube, and then to an amplifier V. - transmitting module in azimuth at an angle that compensates for the azimuthal deviation of the IC from the RSL.

A device that implements this method is a design of a transceiver module in the form of a spherical sector (Fig. 3).

The proposed device is characterized by the use of at least one tier of optical transmitters and at least one tier of optical receivers, which ensure the formation of a sector radiation pattern for receiving transmitted light beams in the required range of angles in azimuth, as well as a goniometric tracking system for the maximum useful signal to adjust the position of the transmitting and receiving module in azimuth.

The lower tier 1 of the module structure has M faces at the base, located at different angles to the vertical with an angular step Δθ _{T, R} / N _{T, R} and containing cells 2 for placing M optical transmitting devices in them, providing a sector radiation pattern for the propagation of transmitted light rays in the range of angles in azimuth in accordance with the formula (1). The second tier 3 of the structure has N edges at the base, also located at different angles to the vertical and containing cells 4 for placing N optical receivers in them, ensuring reliable reception of the transmitted light rays in the required range of angles in azimuth, both in the presence and if there is no line of sight between the transmitter and the receiver.

Thus, the implementation of the claimed method on the claimed device for its implementation allows to reduce hardware costs for creating a multichannel optical communication system by reducing the number of transmission and reception channels of optical signals while maintaining the reliability and communication range in the absence of line of sight between network subscribers when moving and turning mobile communication centers. Reducing the cost and weight and dimensions of an optical communication system expands the possibilities of its use at stationary and, mainly, mobile objects. Consequently, the proposed method solves the problem posed to eliminate the shortcomings of the prototype, especially when organizing a mobile optical communication line, including in the UV-C range.

Claims (4)

1. A method for multichannel transmission of optical signals, which consists in aiming the radiation flux of an optical transmitter in the direction of one of the N _R optical receivers, characterized in that the individual N _T optical transmitters and N _R optical receivers are set in accordance with the sectoral arrangement in the horizontal channel projection along a sector of a circle to form a sector radiation pattern of a transceiver module of a multichannel mobile wireless optical communication system, and the number of devices is selected in accordance with the expression N _{T, R} = Δθ _{T, R} / φ _{T, R} , where Δθ _{T, R} is the range of azimuthal angles of the set of optical transmitting and optical receiving devices, φ _{T, R} is the width of the radiation pattern of the optical transmitting and optical receiving devices, and the azimuth position of the receiving-transmitting module is adjusted using a goniometric tracking system to the maximum useful signal, for which the input radiation is fed to the direction finding device, where the sun-blind filter blocks the incidental solar radiation, then the useful signal is fed to the input of the optical receiver and amplified in the amplifier, then the signal formed in the direction finding device is filtered in a low-pass filter and sent to the executive element for compensating the azimuthal deviation of the signal source from the equisignal direction. 2. A device for multichannel transmission of optical signals according to the method of claim 1, which is a design of a transceiver module in the form of a spherical sector containing at least one lower tier having M faces located at different angles to the vertical, with cells for placing M optical transmitting devices providing a sector radiation pattern for the propagation of transmitted light beams in the required range of angles in azimuth, at least one upper tier having N faces at the base, also located at different angles to the vertical and containing cells for placing N optical receivers in them , in this case, the adjustment of the position of the transceiving module in azimuth is carried out using a goniometric tracking system for the maximum of the useful signal, including a direction finding device, a low-pass filter and an actuator.

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