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Abstract

Content

Introduction

Today, there is a gradual introduction of 5G technology in the mobile cellular network. This allows you to increase the data transfer rate to 10 Gbit/s, the reliability of the connection, as well as the density of the number of connected devices, this is achieved through multi-channel operation and an increase in carrier radio frequencies up to tens of GHz. 5G networks operate at frequencies below 6 GHz and in the millimeter range above 24GHz up to 100GHz. They must be guaranteed to provide sufficient bandwidth to transfer a large amount of data. Free Space Optics technology or atmospheric optical communication lines (AOLS) is a technology for transmitting waves in the optical range in a fiber-free environment, that is, through the atmosphere or even vacuum.

To organize a 5G network using FSO technology, fully optical systems are used, allowing the use of various modulation mechanisms on on the transmitter side and recognition on the receiver side. As a result, the described technology is becoming popular for wireless data transmission. It uses light as a carrier of information between the transmitter and receiver in full duplex mode. Advantage AOLS systems consist in the fact that they provide high safety, since the angle of divergence of light rays is quite small (less than 0.5 degrees). This makes it quite secure, as it is very difficult to intercept such a signal. This solution allows you to organize a network with high bandwidth, as well as make the network more durable and resistant to various environmental conditions (especially fog and various types of precipitation) [1].

The disadvantages of the presented technology include the significant influence of residual phenomena after storms, leading to a high frequency of bit errors and an increase in the error vector. The residual storm state is a level blur at the studied frequency (21-29 GHz).

AOLS provide higher data transmission throughput and improved bit error rate as a result of minor impact multipath and blurring. Based on the playback results, it was found that the AOLS system has a performance increase of 62% compared to RF to achieve a bit error rate of 10-5. There are several hybrid models of transmission over optical wireless communication lines. AOLS compounds depend on various glimatic influences that reduce the availability of the compound. The use of a hybrid system consisting of an AOL connection and a backup interface in the gigahertz range ensures high availability, as well as almost the same data transfer rate [2].

The current direction has the following research problems:

Therefore, from the above, the aim of the work is to find an effective model for the introduction of atmospheric optical communication lines into 5G technology. To achieve this goal, it is necessary to perform a number of the following tasks:

1. Analysis of the proposed solutions

In 2019, a multilevel millimeter cell structure was proposed, where large base stations operating in the range below 6 GHz are accepted as a Poisson point process, and base stations with small cells operating either on millimeter waves or at a frequency below 6 GHz, adopt an inhomogeneous Poisson process.

In 2015, a general system for evaluating the performance of cellular communication systems using millimeter waves was proposed. Using the method Line-of-sight (LOS) areas of LOS and non-LOS base stations are defined as two autonomous inhomogeneous Poisson points. In the light of the proposed system, there were The signal-to-oscillation and resistance ratios are determined. Millimeter waves and velocity are analyzed as components of the geometry of the receiving wire and the base station. The results show that powerful millimeter wave systems can provide the transmission of a large amount of data and much more high information transfer rate than conventional cells. As a result of the current study, a recommendation was made that when selecting the cell size , its territorial location should be taken into account in order to achieve the ideal SINR (Signal to Interference Noise Ratio, that is, to achieve the ideal the ratio of the useful signal to interference) [3].

In 2017, a method was proposed to determine the required number of wavelengths and storage size for large amounts of transmitted data. The implementation of the automatic re-request protocol made it possible to provide a bandwidth of 10 Gbit/s with a millisecond delay of transmitted packets. 5G uplink data transmission requires high bandwidth and a hybrid RF/AOLS for providing communication in the gigabit range. Weather conditions affect RF, AOLS, and MW connections. In high clouds, with the availability of a hybrid connection, the transmission of large amounts of data is available for limited periods and to an incomplete extent. However, at an altitude of 17-22 km, the bit error rate reaches a value less than 10-3 and can be used for transmission of delay-sensitive data [4].

Research for uplink data transmission (AOLS/optics) has shown that when using an ideal fiber optic channel with normal power, speeds of more than 1.5 Gbit/s are achieved. Under ideal conditions and using millimeter-wave radio frequency access by 50%.

A hybrid (AOLS/MW) is proposed to be used for each remote radio unit in order to connect to a centralized radio access network designed for unstable situations occurring during rush hour, or to quickly obtain real-time information with high reliability. Such an organization is promising, it can meet the requirements for direct transmission systems in 5G. Also, this hybrid can be used in poor climatic conditions and provide the necessary quality [5].

5G innovations offer an improved nature of administration with high information transfer rates, which requires the implementation of the IoT concept. Since the connections 5G in the IoT is relevant, it is proposed to upgrade the inclusion using FSO technology, that is, an improved system for fast connection to the AOL network over long distances to use 5G. The current model shows a high level of performance under various climatic conditions [6].

In 2019, bi-directional optical coordination of fiber-free space based on multiplexing with polarization separation was implemented. An AOLS system with a speed of 128 Gbit/s for downlink and 10 Gbit/s for uplink channels has been developed for data transmission. 5G technology has been implemented in a controlled and unmanaged optical wireless communication environment. The frequency of transmission over an optical communication line in the microwave range ranges from 3 GHz to 30 GHz. Various stations of atmospheric optical AOLS lines operate at 5G speeds. The quality factor and maximum transmission separation at a reasonable transmitter power are achieved using separate channels [7-8].

One of the promising hybrid models for the 5G network is RF/AOLS. Both the transmitter and the receiver operate in two ways: the main interface is in the radio frequency version of the Weibull channel, and subsequent connections are made in accordance with the AOLS technology. Both signals are connected in the collector using the method of maximum combination of coefficients, the function of moment formation of the overall signal-to-noise ratio is restored. A new multiplexing-based AOLS data transmission system mode-separated MDM using PolSK polarization shift manipulation technology to extend the data transmission limit within a given system to a transmission range AOLS is 90 km away in clear weather conditions. Such a system shows the best results in various climatic conditions. It is also possible to strengthen AOLS systems with 40 GHz radio frequency connections to ensure accessibility close to the transport class.

A number of studies of the WDM/AOLS system have shown that in clear weather conditions, transmission is performed efficiently on a 180 km line with a transmission rate of 2.5Gbit/s. However, if the line parameters change or there is heavy clouds, showers of varying intensity, it is worth changing the length of the AOLS line.

Under the above conditions, RoFSO data transmission systems based on OFDM with speeds of 40 Gbit/s and 80 GHz can be used by combining MDM of two Hermite-Gauss modes (HG01 and HG03). The essence of this combination is that there are two autonomous radio signals with a frequency of 40 GHz, each of which is optically balanced at a speed of 20 Gbit/s, they are transmitted through the channel of free space under the influence of dynamic climatic conditions and an expanding point of uniqueness.

The combination of innovations in the field of OWC and optical fiber makes it possible to improve the characteristics of AOLS in the following ways. OWC uses infrared light to transmit messages from sender to recipient. OWC is a solution to the "last mile" problem, mostly in overpopulated urban areas. On the other hand, optical fiber also performs It plays a significant role in the optical communication system due to its exceptionally low interference level (0.2 dB/km), low weight and high throughput [9].

One of the solutions is the design and manufacture of a radio pipeline that has a high bandwidth for data transmission at millimeter waves, stable radiation and improved reflection coefficient at a frequency of 28 GHz for solving 5G network problems. For the design and creation of the proposed The FR-4 printed circuit board is used for the receiving device, having a smaller size (5.5x4.35) mm2, a dielectric constant of 4.4, a thickness of 1.6 mm and a deviation from the norm of 0.002. The proposed scheme was planned and reproduced using a test system of a high-frequency structural simulator (High-Frequency Structure Simulation), which depends on the strategy of using limited components. The frequency of transmission of data with full resistance, The power provided by the planned receiving wire is about 4.10 GHz (25.8GHz–29.9 GHz) [10].

In 2018, an equipment pre-configuration scheme was proposed, which includes one power amplifier and an RC channel cascade with repetition of high frequencies to increase bandwidth. Using the proposed pre-allocation scheme, it is possible to achieve a data transmission bandwidth of 3 dB with an optical remote connection in the range from 225 to 942 MHz (as opposed to 289-469 MHz without a pre-allocation scheme). Experimental data have shown that at an optical strength of 2.5 dB - BER 210-3 and 3.6 dB at BER 1-10-9, at an information transfer rate of 1.244 Gbit/s [11].

2. The purpose and objectives of the study

Based on the information provided above, the purpose of the qualification work can be formulated as: the search for an effective model for the introduction of atmospheric optical communication lines into 5G technology. To achieve this goal, it is necessary to solve the following tasks:

Conclusions

Thus, the analysis of the proposed solutions for the implementation of AOLS technology in the 5G network was carried out. To carry out such events, it is necessary to use hybrid systems, among which: RF/ AOLS; AOLS/optics; AOLS/MV; bidirectional optical coordination of fiber-free space based on polarization division multiplexing; AOLS data transmission system based on mode division multiplexing using polarization shift manipulation technology; WDM/AOLS; RoFSO data transmission system based on OFDM; AOLS/OWC.

The introduction of AOLS technology to improve the performance of the 5G network is currently a fairly non-trivial task that requires certain technological, technical and economic costs. Research in this area shows that the use of hybrid models of AOLS systems will allow you to organize a 5G network with higher reliability and bandwidth. Thus, combining AOLS and 5G can potentially provide high-speed and reliable communication services in regions where traditional wired or wireless communication infrastructure is unavailable or impractical. Such integration It can potentially provide broadband communication channels between base stations, uplinks and even end users.

When writing this essay, the master's thesis has not yet been completed. Final completion: May 2025. The full text of the work and materials on the topic can be obtained from the author or his supervisor after the specified date.

References

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