Almost all systems of train radio communication, station communication with moving objects, repair and operational, service and operational radio communication, etc. are implemented in the ranges of 2, 160, |530 and 450 MHz on radio stations with angle modulation with fixed attachment of communication channels. Only some subsystems of the Transport system provided for the use of the principle of equally accessible channels (trunking).

The improvement of technological railway radio communication networks is carried out in two stages, taking into account the stages of development of the railway communication network and the creation of a single integrated digital communication network.

First stage.

Introduction of train radio communications in the hectometer range (2 MHz) based on modernized radio equipment: RS-46M, RS-23M, SR-234M, US-2/4M, dual-band radio stations RV-1M, RV-1.1M.

Implementation of a train dispatcher's duplex radio communication system "Transport" in the 330 MHz band on the main routes of the railway network of Siberia and the Far East, which will make it possible to organize radio communication networks when using three-band RV-1M radio stations on locomotives.

Train dispatch radio communication is created in two bands - decimeter (330 MHz) and hectometer (2 MHz).

In the 330 MHz band, the main dispatch communication channel is organized, providing continuous radio communication between the DNC, ECC and the train locomotive dispatcher (TNC) with train locomotive drivers within the entire dispatch area.

The duplex train dispatch radio communication network provides a test check of the serviceability of stationary and portable equipment with display of control results. A backup dispatch communication channel is organized in the hectometer range, used mainly for radiotelephone conversations between dispatchers and drivers.

Communication of train locomotive drivers with the EAF and at crossings is organized in the hectometer (2 MHz) and meter (160 MHz) ranges.

Communication between train locomotive drivers and locomotive depot duty officers, paramilitary guard gunners, and repair work managers with various categories of subscribers equipped with portable radio stations is organized in the meter wavelength range (160 MHz) with the ability to receive fixed commands and messages from specialized floor-mounted devices or portable ones on the portable radio station radio stations (“Attention, moving”, “Track repair”, “Fire on a train”, “Emergency on a train”, etc.).

Communication between train locomotive drivers and drivers of oncoming and following trains is organized in the hectometer and meter wavelength ranges, and with driver assistants when the latter leave the locomotive cabin - in the meter wavelength range. At the same time, driver assistants must have portable radio stations.

Communication between the head (foreman) of a passenger train and the driver of the train locomotive, with those on duty at stations and crossings and various categories of workers equipped with portable radios (on duty at the platform, at the station, police officers, etc.) is organized in the meter wavelength range (160 MHz).

The intra-train communication and public address network ensures the transmission of information to train passengers and communication between the train chief and crew members.

3. Development and implementation of train dispatch radio PRS460 in the main directions of the road network of the European part of Russia and the Urals regions. At the same time, dual-band duplex-simplex radio stations of the decimeter (460 MHz) and meter (160 MHz) ranges will be installed on mobile objects of railway transport. During the transition period, hectometer range radio stations 42RTM-A2-ChM (ZHR-K-LP) or RK-1 will remain in operation.

Station and repair and operational radio communication (RORS) using fixed channels in the meter wave range (160 MHz). The development trend of PORS is associated with the introduction of networks that use equally accessible channels (trunk networks).

Radio communication using equally accessible channels in the decimeter (460 MHz) wave range.

Trunking networks should include subscribers of management personnel, as well as subscribers of the following station and repair-operational communication networks: track repair services, power supply, communications and signaling; paramilitary security workers; the head of a passenger train with duty officers at stations and line police stations; services capital construction; loading and unloading sites; cargo and commercial work; locomotive radio networks; commercial inspection points for wagons; transport and forwarding enterprises for the delivery of containers and cargo; radio networks of fire and recovery trains.

Second phase.

Creation of digital cellular mobile radio networks adopted by the UIC (GSM-R) in accordance with Recommendations UIC-751.4, which will allow organizing channels that ensure the transmission of critical commands in the train traffic control system; train dispatch radio communication to ensure communication between the dispatch apparatus and train locomotive drivers; train technological radio communications for solving all technological problems, including station and repair and operational radio communications (except for shunting and hump communications), as well as passenger service radio communications due to the excess capacity of train technological radio communications and with access to the ZhATS network.

Organization of passenger service communications and intra-train radio communications using railway technological radio communications, public land mobile radio communications and mobile satellite communications.

Intra-train radio communications must be built in accordance with the UIC Recommendations (TLS-568, taking into account the requirements for train radio communications ShS-751.3) and provide:

Loud-speaker notification of passengers within the entire train by the train master and the train dispatcher using train dispatch radio communications; within the carriage - by the train conductor;

Communication between the train chief and the conductors and locomotive drivers within the train, and at stops - and within the platforms;

Communication between train passengers and telephone exchange subscribers, subscribers on other trains, access to the public telephone network; communication with subscribers included in the railway technological train radio communication system operating in the mode of digital trunking radio networks and/or in the GSM-R system.

The need to improve technological radio communications is due to the following tasks facing railway transport:

Improving the management structure and technology of transport;

Increasing employee productivity and reducing operating costs;

Improving traffic safety through the development of train traffic control systems via radio channel;

Improving the quality of passenger service, developing the service sector and commercial passenger transportation.

Requirements for the technological radio communication system by railway transport operational services:

Increasing the number of subscribers to railway radio communication networks and equipping employees of all services of the Ministry of Railways with radio equipment;

Expanding communication zones and increasing the reliability of communication of the dispatcher apparatus when organizing train and shunting radio communications;

Organization of radio communication networks for workers in repair and maintenance departments;

Providing a number of categories of railway transport subscribers with mobile (wearable) radio terminals with the ability to establish operational communication in telephone mode or data transfer mode with the apparatus of the Ministry of Railways, departments and road departments via the general technological communication network of the Ministry of Railways.

At the present stage of development of mobile railway radio communications, the technologies for its use can be significantly changed. Until now, radio communication has been used mainly in radiotelephone mode and only in certain technological processes, for example, to control shunting locomotives or locomotives of connected trains - in the mode of transmitting telemetric information.

Currently, significant attention should be paid to solving the problems of automating train traffic control over a radio channel, monitoring transport technological processes and information support for automated control systems.

An analysis of the capabilities of modern mobile radio communications shows that their use makes it possible to solve many applied problems, in particular:

Automatic control of shunting and hump locomotives at stations;

Monitoring and transmission of diagnostic information about the condition of the train and locomotive to depots and maintenance centers;

Notifying train drivers and on-board controls using equipment for monitoring the technical condition of rolling stock while the train is running (DISK, PONAB, etc.);

Interval control of train traffic, including for high-speed lines,

Semi-automatic blocking on inactive lines;

Fire and security alarm in depots, places where rolling stock is parked;

Organization of radiotelephone communications, transmission of fax and video information from the site of restoration work, ensuring the possibility of negotiations and transmission of information to the level of the Ministry of Railways of Russia, departments and departments of railways;

Notifying repair crews and train drivers about approaching the place of repair work;

Transfer of telemetric information for the management of stationary power supply facilities, traction substations, barriers at unguarded crossings, compressor stations, etc.;

Control of connected trains of increased weight and length;

Identification and control of the location of trains at road junctions, boundaries of dispatching areas and stations with the transfer of data about the train, including information from the full-scale sheet in real time to the road control center in the DISPARK system, etc.

Monitoring the location of trains transporting particularly valuable and dangerous goods;

Access services to the Express-3 system for ordering and purchasing tickets on trains.

Based on a detailed study and analysis of the needs of all railway transport services for the transmission of voice information and data and in order to ensure improved management of the transportation process based on meeting these needs, “Operational and technical requirements for the digital radio communication system of Russian railway transport” have been developed.

Digital radio systems

In connection with the modernization of technological radio communication systems, the Ministry of Railways of Russia is making a transition to digital systems. A TETRA trunking communication system and a GSM-R cellular communication system are at the testing stage.

general characteristics TETRA standard, The TETRA standard describes a digital radio communication system that provides a wide range of telecommunications services. These include individual and group calls, access to the public telephone network, data transfer, as well as various additional services.

The most important property of the TETRA standard is that it allows you to organize the simultaneous operation of many independent virtual networks belonging to different departments and organizations within the same system. Subscribers of each of them, communicating with each other, will not feel the presence of “foreign” networks in any way. At the same time, if necessary (for example, in emergency situations), their interaction can be quickly organized.

The TETRA standard provides reliable information security. For this purpose, a system of measures is provided, including mandatory encryption of radio communications. Unauthorized access to a TETRA standard system is impossible - with each connection, the subscriber and the network conduct mutual authentication using a crypto-resistant algorithm. Users with high privacy requirements can use the service of end-to-end transmission of encrypted information - this method eliminates the interception of messages not only on the air, but also in the network infrastructure.

TETRA standard systems provide subscribers with a wide range of data transmission services - from sending short text messages to the organization of channels allowing the exchange of information at a speed of 28.8 kbit/s. A TETRA network subscriber can simultaneously use voice and data services. In addition, TETRA subscriber radios that have a built-in graphic display and support the WAP (Wireless Application Protocol) protocol can access departmental information resources. corporate networks and the Internet.

The TETRA standard allows each subscriber to be assigned a certain priority level. Users with high priority have unconditional right to access the network - even if all channels are busy, the system will immediately break one of the current connections upon receipt of a request and provide a communication channel. The TETRA standard uses special speech signal processing methods that ensure not only accurate transmission of voice timbre, but also preservation of intelligibility when working in conditions of strong external noise (for example, at construction sites, railway stations, etc.). When a subscriber moves from one service area to another, the conversation is not interrupted.

Thus, the TETRA standard allows the creation of digital radio networks that fully meet the needs of a wide variety of subscribers. Despite the fact that the standard today includes all the specifications required by manufacturers, work to expand it continues. Thus, technology is being developed that will significantly increase the radio communication range - up to 100 km. In addition, the TETRA PDO specification is being improved - a special version of the standard focused only on packet data transfer.

According to the V+D specification implemented in the TETRA standard, the user is provided with one of three services for data transmission: circuit switched data (CD), packet switched data (PD) and short message service (SDS). The CD method is primarily intended for transporting large amounts of data on top of the underlying channel traffic, with each 25 kHz channel using one of four time slots. This is where the TETRA standard provides the required quality of service, since the necessary bandwidth can be reserved on demand. If the user needs to increase throughput, it is possible to combine two to four time slots and establish an end-to-end communication channel, and to increase speed the user will have to reduce the security level of such a channel.

As for the PD mode, today this is the most interesting and promising method, which is mainly due to global trends, in particular, the Internet. The total proliferation of the IP protocol and, as a consequence, IP-based applications has found its application in TETRA networks. IN in this case the mobile radio acts as the IP client and the TETRA network as the transport medium. This scheme is characterized by increased flexibility and reliability due to the existence of various radio signal delivery paths, readiness for increased traffic, the ability to connect almost any computer equipment to the radio station and, of course, support for standard products and applications.

Functional diagrams for constructing various communication networks of the TETRA standard are presented as a set of network elements connected by certain interfaces. TETRA networks contain the following main elements:

Base transceiver station BTS (Base Transceiver Station) is a basic stationary radio station that provides communications in a certain area (cell). Such a station performs the main functions related to the transmission of radio signals: pairing with mobile stations, encryption of communication lines, spatially diverse reception, control of the output power of mobile radio stations, control of radio channels;

Base station control device BCF (Base Station Control Function) - a network element with switching capabilities that controls several base stations and provides access to external networks, and is also used to connect control panels and terminals for operational and maintenance;

Base Station Controller BSC (Base Station Controller) is a network element with greater switching capabilities compared to a BCF device, allowing data exchange between several BCFs. BSC has a flexible modular structure that allows the use of a large number of interfaces of different types;

Dispatch console is a device that is connected to the base station controller via a wired line and ensures the exchange of information between the operator (network manager) and other network users. Often used for broadcasting information, creating user groups, etc.;

Mobile station MS (Mobile Station) - a radio station used by mobile subscribers;

Fixed radio station FRS (Fixed Radio Station) - a radio station used by a subscriber in a specific location;

Maintenance and operation terminal - a terminal connected to the BCF base station control device and designed to monitor the state of the system, diagnose faults, record tariff information, make changes to the subscriber database, etc. Using such terminals, the local network management function LNM (Local Network Management) is implemented. Thanks to the modular principle of equipment development, TETRA communication networks can be implemented at different hierarchical levels and different geographical extents (from local to national). Database management and switching functions are distributed throughout the network, ensuring fast call transfer and maintaining limited network availability even if individual elements of the network are lost.

At a national or regional level, the network structure can be implemented on the basis of relatively small but complete TETRA subnetworks, interconnected using an ISI to create a common network. In this case, centralized network management is possible. A variant of constructing such a network is shown in Fig. 21.7.

Each TETRA subnetwork performs its own control and switching functions, and also provides the ability for higher-level centralized control. The subnet structure depends on the load as well as the requirements for communication efficiency. If channel reservation is not required, it is possible and sufficient to create a subnet according to the star configuration. When using linear paths, a TETRA subnetwork can be implemented as a long line (chain). In this case, each module of the BCF base station control device, along with the required communication range, provides local access to external networks. The simplest TETRA subnet configuration includes only one BCF module.

Communication networks of the TETRA standard provide for various methods of ensuring fault tolerance, allowing, in the event of failure of individual network elements, to maintain full or partial functionality, possibly with deterioration of a number of parameters,

such as connection establishment time, etc. For national-level networks, as a rule, several alternative routes are used to connect regional-level networks. In regional networks, such alternative routes are used to connect base station controllers. In addition, for regional networks, mutual copying of databases in base station controllers is provided.

General characteristics of GSM-R. The GSM-R radio communication system is developed on the basis of the GSM cellular standard and is focused on meeting the needs of European railways in the exchange of information with moving objects, as well as creating conditions for the implementation of traffic control systems using radio channels through the use of 4 MHz bands in the 876- 880 MHz and 921-925 MHz (Fig. 21.8).

The railway section is divided into several areas covered by RBC control centers. The system generates control commands, controls speed, and determines the location of the train. During communication between the train and the RBC center, duplex transmission is possible. For example, the center transmits permission for a train to move, and the train transmits information about its location.

The GSM standard has been adopted International Union Railways (UIC) in 1993 as the base technology for the implementation of a railway digital communications system. But since this standard did not have the service necessary for professional systems, in 1993 the UIC made a request to ETSI (European Telecommunication Standards Institute) to implement additional ASCI properties. These include advanced multi-level priorities, redundancy, broadcast services voice notification and voice group call. Along with ASCI to meet the requirements of railways for train, shunting radio communication services, data transmission for train control, telecontrol, etc. Functional addressing, location-based addressing, and high-priority call processing must be implemented.

The GSM-R network can be divided into several subsystems:

On-board devices;

Stationary devices;

Control center.

The division of tasks between the three control subsystems is carried out as follows:

The control center takes over the management of routes and provides trains with conflict-free assignment of track sections (regulating the order of trains);

On-board devices issue tasks to stationary devices in accordance with their assigned routes and control the movement of trains;

Stationary devices, in turn, perform the functions of managing and monitoring switches, approaches to passenger platforms and crossings.

Each of the subsystems has its own access to the radio communication network and is capable of interacting with other subsystems. The distribution of security functions between several subsystems required the formation of a single database. This is necessary primarily to coordinate data on trains and in the control center. Therefore, the subsystems work with data from a single line atlas, which contains all the information describing this line. This includes, along with topological information (line model, location of switches and crossings), data on the maximum permissible speeds and addressing in the radio communication system.

The GSM-R network consists of cells located along the railway or in the station area. Each cell cell is equipped with one or more transceivers depending on the load. Each base station controller is assigned to specific cell numbers. The base station controllers are connected to the MSC (Mobile Switching Center)/VLR (Visitor Location Register) control center. The MSC establishes external connections and provides an interface with other networks (Fig. 21.9), where the following abbreviations are used:

AUC (Authentication Center) - authentication center;

BSC (Base Station Controller) - base station controller;

BTS (Base Station System) - base station transceiver;

GCR (Group Call Register) - call group register;

EIR (Equipment Identification Register) - equipment identification register;

SMS (Short Message Service) - short message service;

VMS (Visitor Management Server) - motion management server;

OSS (Operation System Server) - control center server;

OMC (Operation and Maintenance Center) - control and maintenance center;

SCP (Service Control Point) - communication services control point;

IN (Intelligent Networks) - intelligent network;

PABX (Private Automatic Branch Exchange) is an automatic dedicated channel switch.

All network components in the GSM-R standard interact in accordance with the ITU-T SS.No (CCITT SS No. 7) signaling system.

The switching center serves a group of cells and provides all types of connections to the mobile station.

LITERATURES

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INTRODUCTION 3

TRAIN CONTROL SYSTEMS

Chapter 1. Elements of traffic control systems 6

System classification 6

General information about system elements 9

General information about relay 11

DC relay 16

AC Relay 24

Transmitters and electronic devices 26

Chapter 2. Traffic lights 31

Purpose, types and installation locations of traffic lights 31

Traffic light signaling 37

Classification and design of traffic lights 43

Chapter 3. Power supply of automation and telemechanics devices.. 46

Power supply equipment 46

Power systems 49

Chapter 4. Track circuits 52

Design, principle of operation and purpose of track circuits.. 52

Classification of track circuits 56

Basic operating modes of track circuits 58

Reliability of track circuits 61

Track circuit diagrams 63

Chapter 5. Semi-automatic blocking 73

Purpose and principles of construction

semi-automatic locking 73

Ways to record a sequence

and control of train arrival 78

Relay semi-automatic blocking of the GTSS 80 system

Chapter 6. Automatic blocking 91

General information and classification of automatic locking systems 91

Alarm systems 94

Principles of DC auto-blocking 97

Principles for constructing a double track

AC auto-lock 107

Chapter 7. Automatic locomotive

alarm and hitchhiking 119

General information 119

Automatic locomotive

continuous type alarm 121

Automatic locomotive signaling

single row with continuous communication channel 129

Automatic brake control system 130

Chapter 8. Fencing devices at crossings 133

Purpose and types of automatic

fencing devices at the crossing 133

Control crossing traffic lights

and automatic barriers 139

Construction of a railway crossing barrier 143

Chapter 9. Electrical centralization of points and signals 147

Purpose and classification of systems

electrical centralization 147

Equipment of the station with devices

relay centralization 151

Electric switch drives 170

Arrow control circuits 175

Relay centralization of intermediate stations 179

Relay centralization for medium and large stations 189

Principles of block construction

route-relay centralization 201

Microprocessor systems ETs 211

Chapter 10. Mechanization and automation

work of sorting humps 223

Principles of mechanization and automation

work of marshalling yards 223

Hump car retarders 227

Hill control panel 229

Comprehensive automation

work of marshalling yards 237

Actions of the slide attendant in case of disruption of normal operation

automation and mechanization devices 241

Chapter 11. Dispatcher centralization 244

General information 244

Control and monitoring devices 246

Basic requirements

to the train dispatcher and the duty officer at station 254

Chapter 12. Supervisory control

for train movement and technical diagnostic systems 256

General information 256

Frequency dispatch control system 258

Automated system

dispatch control ASDC 261

Telecontrol system 262

Condition monitoring systems

rolling stock on the move train 264

Chapter 13. Train traffic safety

in case of malfunction of signaling devices 271

Ensuring safe train movement

with semi-automatic blocking 271

Organization of safe train movement under AB 274

Organization of safe traffic at crossings 277

Organization of safe traffic

trains in case of malfunction of EC 281 devices

Section II COMMUNICATION

Chapter 14. Features and purpose of railway communications 291

State of the communication network of the Ministry of Railways of Russia 291

Basic concepts and definitions 292

Types of railway communications and their purpose 293

Prospects for the development of telecommunications

on railway transport 295

Chapter 15. Communication lines 297

Purpose and classification of communication lines 297

Overhead and cable communication lines 298

Fiber optic communication lines 302

Chapter 16. Telephone sets and switches 306

The principle of telephone speech transmission.

Two-way telephone transmission circuit 306

Design of telephone sets.

Telephone sets of technological communication 309

Telephone switches.

Purpose and principle of operation 313

Operational switches

and operational-technological communications 315

Digital telephones and switches 319

Chapter 17. Telegraph communications and data transmission 324

The principle of organization and purpose of telegraph communication 324

Telegraph devices.

Automatic telegraph communication 328

Creation of a data transmission network for Russian railways 334

Chapter 18. Automatic telephone communication

on railway transport 339

Principles of automatic switching.

General information about PBX systems 339

Coordinate system automatic telephone exchanges and quasi-electronic automatic telephone exchanges 344

Digital PBX 347

Operational and technological equipment

time-switched communications 349

Chapter 19. Multichannel transmission systems 352

Features of communication channels and methods of their compaction 352

Analog multichannel transmission systems 358

Digital multi-channel 360 transmission systems

Digital primary network 360

Chapter 20. Technological telephone communication

on railway transport 367

Classification and purpose

technological communication 367

Selective calling systems 375

Trunk and road technological communications 382

Operational and technological communications

railway departments 385

Station technological communication 391

Unified digital platform for organizing general technological and operational-technological communications 395

Chapter 21. Radio communications 399

Basic concepts 399

Station radio communication 402

Train radio 404

21.4. Repair and operational radio communication 406

Radio relay communication 408

Prospects for the development of railway radio communications 411

Digital radio systems 416

REFERENCES 425

In given units.

Information and communication technologies and services are currently a key factor in the development of all areas of the socio-economic sphere. As throughout the world, in Russia these technologies are demonstrating rapid growth rates. Thus, over the past five years, the growth of the communication services market in our country has been about 40% annually.

A special investment fund appeared for the first time in the structure of federal budget expenditures for 2006. The directions of expenditures of this fund are the subject of heated discussions in society and government structures. In particular, the investment fund could also finance telecommunications projects, primarily in order to create a digital infrastructure on a nationwide scale.

The reliability and availability of communications and telecommunication services in our country has long been an acute problem, and information services such as high-speed Internet access, video communications, cable television, IP telephony, etc., are developing mainly in Moscow and St. Petersburg, although all residents of Russia feel the need for such services.

And while we are having debates about whether it is worth allocating funds from the investment fund to such infrastructure projects as the construction of interregional digital highways (which, by the way, could serve as a catalyst for the development of other segments of the IT industry and the economy as a whole), all over the world The time for a dramatic increase is approaching bandwidth digital information networks, which will inevitably entail the emergence of qualitatively new types of services that may no longer be available to us.

Thus, in September 2005, the next iGrid conference and exhibition were held in San Diego (USA) (http://www.igrid2005.org/index.html). This is an international movement that develops the idea of lambdaGrid: the word lambda denotes wavelength, and Grid “grid” with a hint of a geographical network of parallels and meridians. In general, this movement is not so new, and its technological principles have long been developed. We are talking about DWDM technology (Dense Wavelengh-Division Multiplexing), that is, global multiplexing of digital communications. Perhaps the closest and fairly accurate analogy for understanding the basics of this technology is the transition from the telegraph and spark radio of Marconi and Popov to modern multi-frequency radio broadcasting, that is, the network world is moving from primitive technologies for data transmission via optical fiber to simultaneous use when transmitting waves of different lengths. Simply put, signal receivers/transmitters (DWDG-enabled FO tranceiver) turn from black and white to multi-colored. At the same time, the opto-

the conductor already has a fairly wide transparency band, or rather, a wide band of confinement of the light beam inside the optical fiber with low emission losses not along the fiber axis, as a result of which there is no need to lay new cables.

In addition, new DWDM transceivers are quasi-duplex, that is, one fiber can transmit data in both directions simultaneously. In numerical terms, this means that over current ten-gigabit fiber optic channels, DWDM technologies will allow transmitting up to 160 streams simultaneously, and we are talking about long-distance trunk channels, including transcontinental ones. It turns out that all of the so-called progressive humanity suddenly receives such an unexpected gift as an increase in network capacity by two orders of magnitude. In addition, the presence of many free channels will allow you to allocate them as needed and send data streams in parallel instead of sequentially transmitting them over one channel, as was the case before. Naturally, this requires new hardware and software solutions and requires the integration of today's network owners into a single information infrastructure.

Unfortunately, such technologies will not reach Russia very soon, because so far, according to the map of world digital communications, our country is not filled with fiber optic lines.

Russian characteristics

Serious changes are expected in Russia, primarily in the field of organizing telephone communications PSTN (Public Switched Telephone Network public telephone network, PSTN). It is expected that already this year subscribers will have the opportunity to choose a long-distance and international communication operator. In addition to Rostelecom, Interregional TransitTelecom (MTT), Golden Telecom, TransTelecom and others plan to provide their services, although only Rostelecom is operating today without any particular complaints. In principle, it should be possible to use the services of several companies at once, that is, the user will choose whose minutes on the desired route are cheaper. Each operator will be assigned a code starting with the number “5” (51, 52, etc.), which will need to be dialed after connecting to the intercity. In the meantime, after dialing the usual long-distance number eight, the subscriber will get to the usual Rostelecom. And those who are already cheaper to call using alternative operators today need to write a statement to their telecom operator, and then the G8 will begin connecting them to the appropriate network.

The share of time-based payments for fixed-line telephone calls continues to increase, gradually catching up with the cost of mobile communications. According to the new version of the communications law that came into force on January 1, 2004, operator companies are required to provide subscribers with two types of tariffs: time-based and fixed (of course, if technically possible). Currently, not all interregional companies (IRCs) of Svyazinvest, even at the level of regional centers, are equipped with systems for time-based recording of the cost of negotiations; most do not have enough money for technical re-equipment and the introduction of billing systems. And yet, in many regions of RTOs, already this year subscribers were given the opportunity to pay for telephone calls in a new way.

And in accordance with the resolution of the Government of the Russian Federation “On state regulation of tariffs for public telecommunications and public postal services” approved on October 24, 2005, telecom operators, if technically possible, must establish three mandatory tariff plans:

with a time-based payment system;
with a subscriber payment system;
With combined system payment, according to which the meter turns on after “talking out” a certain amount of time.

In addition, the operator will have the right, in addition to these basic tariffs, to introduce any number of other tariff plans, and the consumer can choose the one that he likes and can afford.

At one time, during the controversy over the “time-based payment”, many copies were broken, and as a result, the Duma rejected the first version of the law on communications, which envisaged the forced transfer of all fixed-line subscribers to time-based payment for calls, and the current law was adopted, giving citizens the right select the tariff type. Of course, not all regions have this “technical ability” to install a time-based payment system (for this, many need to radically change the equipment, and, as always, there are not enough funds for this), but in some regions many subscribers already use the “time-based” system , if only for the reason that at one time they were forcibly transferred to it, in particular, these are almost all subscribers of Uralsvyazinform. In other regions where such technical capabilities are available, but there was no forced transfer, approximately half of the subscribers independently switched to “time-based”.

Finally, OJSC Moscow City Telephone Network (MGTS) is developing three tariff plans for local telephone communications for its subscribers - individuals. MGTS submitted an application for approval of tariff plans in December 2005, and approval itself may occur in early 2006. MGTS has long had the technical ability to carry out time-based recording of the duration of local telephone connections: both time-based accounting systems have been implemented at telephone exchanges and a billing system.

MGTS is the main telephone operator in Moscow, and the subscription fee for individuals is 200 rubles, which is currently slightly higher than the national average. Thus, today the average monthly fee for a fixed-line subscriber in Russia is 160 rubles, while the break-even point for the provision of such a service, according to the Ministry of Information and Communications, is 210 rubles. And if you plan to further expand communication services, then, according to officials, the average monthly fee should be raised to 230-250 rubles, and such an increase will undoubtedly follow in the next two to three years. However, if today we sharply raise the average subscription fee by 50 percent, then fixed-line subscribers will become en masse abandon such lines in favor of mobile telephony. Otherwise, fixed-line communications will be almost equal in cost to mobile communications, but with the incomparably greater convenience of the latter. For example, in Moscow, a time-based payment for outgoing calls is expected to be up to 1.8 rubles, which is approximately $0.06, that is, the same amount as a not-so-cheap cellular operator has to pay for 1 minute of an outgoing call on its network. And since the growth of subscription fees in all regions of the country is inevitable, mobile communications are becoming more and more attractive.

With the entry into force of January 1, 2006, the rules for the provision of telephone services approved by the Government of the Russian Federation, the re-registration of a home telephone from one owner to another will not exceed the amount of one monthly subscription fee for telephone services (currently the fee for re-registration of a telephone is charged in the amount of the fee for its installation and amounts to several thousand rubles). In addition, the regions will now have to hold competitions for the right to provide universal telephone services using payphones, as well as for the right to provide communication services for data transmission and provision of access to the Internet.

Meanwhile, the State Duma decided to equalize the responsibilities of mobile and fixed telephony and adopted in the first reading the draft law “On Amendments to Article 54 of the Federal Law “On Communications””, which is supposed to legislate the principle of free all incoming calls to any telephone numbers for the called person. In accordance with this bill, any telephone connection established as a result of a call by another subscriber, other than one established with the help of a telephone operator at the expense of the called person, is not subject to payment by subscribers.

If such a law is adopted, it will be another blow to the fixed-line communications system.

IP telephony

IP telephony (or VoIP, Voice over Internet Protocol) is another technological innovation that came to us along with the Internet and indicates that the world will no longer be the same. VoIP is essentially a technology that allows you to reduce the cost of long-distance and international calls by 3-5 times. This happens due to the fact that the main part of the path of the voice signal goes over the Internet in digital form, and this costs much less money and allows you to achieve more High Quality connection than using conventional analog lines.

Over the past year, sales of communications systems based on IP telephony have surpassed those of solutions based on a standard telephone line. From June 2004 to June 2005, sales of VoIP systems increased by 31%, while standard solutions sold 20% worse (as Networking Pipeline writes, citing the analytical company Merrill Lynch). This bidirectional process appears to be why the overall phone system market grew just 2% year over year to $2.24 billion.

Internet providers and telephone operators are actively developing the IP telephony market in all developed countries. For example, in the United States today such service packages are offered where for about $25 you can sign up for a monthly subscription, which allows you to call any subscribers in the United States and Canada for a whole month without any restrictions. These innovations are actively encouraged by the American authorities, who, as is known, have set as their goal the development of Internet technologies in their country and, in connection with this, have almost completely exempted the Internet industry from taxes in the coming years. It is obvious that with the advent of cheap VoIP services available to the mass consumer, according to all the laws of a market economy, any normal person will use them, and not the more expensive services of standard long-distance and international operators. Russian economists estimate the turnover of the currently established IP telephony services market in our country at $300 million per year. Various companies are now operating in this market, both VoIP departments of large telecommunications companies and small local operators.

But if in developed countries this situation is considered natural, in other countries it raises serious concerns and, first of all, among monopolistic operators of traditional communications, who see the development of IP telephony as a direct threat to their profits. And contrary to the laws free market, some monopolistic companies are trying to prevent this development, using all the methods available to them. Thus, in Costa Rica, where a single national telephone provider has dominated the market for many years, they are currently trying to regulate the activities of VoIP firms by imposing additional taxes on them as intermediary companies that generate added value. Moreover, it is even proposed to ban the work of VoIP providers altogether, equating their activities to criminal activity. Many Costa Rican experts assess this prospect as catastrophic for the economy of this country, since Lately In Costa Rica, the remote programming (outsourcing) industry is actively developing, for which the ability to make cheap international calls is a significant help.

Our companies are not lagging behind the Costa Ricans either - traditional monopoly operators such as Rostelecom or MGTS, who are also trying to use administrative resources to declare the business of VoIP firms illegitimate. The use of administrative resources for commercial purposes, according to representatives of independent VoIP companies, can be seen, say, in the resolution of the Government of the Russian Federation, which on March 28, 2005 introduced an instruction developed under the control of the Ministry of Information Technologies and Communications entitled “Rules for connecting telecommunication networks and their interactions." According to specialists from these companies, these rules actually prohibit the provision of IP telephony services, establishing for them obviously impossible obligations and the strictest restrictions. As a result of such pressure on local VoIP providers, making an IP telephony call to Russian regions or CIS countries costs 2-3 times more than to America and even Australia.

However, liberalization of the long-distance communication market cannot be stopped in any case, since this is one of the key requirements in negotiations on Russia’s accession to the WTO (World Trade Organization).

Internet via modem

Thus, in 2005, tariffs of Svyazinvest companies increased by 20-25%, during

2004 by 30%, and the rate of growth of fixed-line tariffs in 2006 is again projected at 30%. In particular, tariff increases will occur when alternative tariffs for RTOs are approved. However, we should not expect a nightmarish devastation of our wallets from the new procedure for the provision of telephony services; on the contrary, those who do not talk on the phone for very long will even be able to save on time-based fixed-line communications.

It’s a different matter when accessing the Internet via a PSTN modem (dial-up), where you can no longer expect concessions from time-based services. And, apparently, this method of accessing the Internet will gradually become a thing of the past. Of course, PSTN Internet providers, even in conditions of no alternative hourly service, find ways to ensure that their subscribers do not pay for the Internet by the minute, that is, according to the telephony operator’s bills. For example, in those cities where time-based payment is already used, providers introduce a callback: you call the modem pool, the connection is interrupted, and you receive a callback from the pool as an incoming call. Windows XP, by the way, handles such a callback perfectly, and therefore the connection is at the expense of the Internet provider. The ways in which PSTN providers exist are also through various agreements with telecom operators, which provide for special (possibly short) telephone numbers, by calling which you can connect without a monthly fee. However, in the same way you can agree with the telephone operator about installing ADSL equipment (DSLAM) on communication nodes, and as a result move to more advanced technologies for accessing the Internet that do not occupy telephone lines at all.

In addition, the manufacturing quality of PSTN modems themselves is getting worse and worse, because the production of modems for dial-up communication lines has long been no longer an advanced branch of the IT industry. In the civilized world, this type of communication is becoming irrelevant due to the spread of high-speed information highways and due to their availability for the mass consumer; here the main competitor to modem communication is ISDN, ADSL, fiber optic communication lines, Wi-Fi, and even cellular data transmission systems such as GPRS, etc. Accordingly, manufacturers are losing interest in releasing new products, and some have already curtailed the production of analog modems. And since sales volumes of this equipment for the advanced and most profitable areas of the market have fallen sharply, manufacturers are trying to reduce the cost of the hardware of their products as much as possible, which, naturally, negatively affects the quality of communication using such modems.

In addition, due to the general improvement in the quality of telephone communications in those countries where analog modems are still sold, manufacturers are no longer concerned about ensuring that their equipment works on the noisy lines of outdated telephone exchanges. Thus, modern analog modems can only be used as a backup communication channel: where they still work reliably, alternative methods of accessing the Internet, as a rule, are already well developed, and where such technologies are not developed, even modern analog modems they work poorly. And there seems to be no way out of this vicious circle.

The Russian broadband access market is growing primarily due to the individual segment: the number of home connections in the first half of 2005 increased by more than 1.5 times and reached 870 thousand subscribers. Thus, 85% of new broadband connections come from individual users and only 15% from the corporate segment of the market.

The obvious growth leader among broadband technologies is DSL: the number of DSL connections grew by more than 60%, and if we take into account only home connections, the growth of the DSL market in this segment was even more than 80%. But even despite such impressive dynamics of DSL operators, the most popular way to connect home users remains Ethernet from home networks; in total, they still have 2-3 times more subscribers than DSL operators.

However, Russia looks good only in terms of growth dynamics: the number of broadband connections in our country, according to international news agencies, increased by 52%, while the increase in the world as a whole was only 20%, and in Eastern and Central Europe (without accounting for Russia) approximately 30%. Thus, in terms of dynamics, Russia is ahead of all the largest broadband access markets, second only to the Philippines, Greece, Turkey, India, the Czech Republic, South Africa, Thailand and quite a bit to Poland.

However, in terms of the total volume of broadband connections, Russia's position is very weak; according to the Point-Topic agency, its share accounted for only 0.7% of all broadband connections in the world in mid-2005. Only about 1.5 million broadband connections in Russia today look unimportant compared to 53 million in China, 38 million in the US or even 3.5 million in the Netherlands. Nevertheless, on the first try, Russia entered the Top 20 of the Point-Topic ranking in terms of the number of broadband connections and, according to preliminary data, increased this number by 85% by the end of the year. As a result, our country is today in 17-18th place, ahead of not only Poland, but also the more developed Sweden. By the way, the coverage of PSTN subscribers with broadband communication services (that is, the potential opportunity to connect to ADSL) only in the central region (excluding Moscow), according to Svyazinvest OJSC, amounted to 3,746,825 people, and yet the real number of ADSL access subscribers is not exceeds 224 thousand subscribers in this region.

The situation is even worse with the penetration of “broadband” into the regions; today there are only 0.9 connections for every 100 residents. According to this indicator, Russia is 10-30 times inferior to South Korea, Japan, the USA, as well as leading countries Western Europe and 4 times the average of new members of the European Union. Even in China, the penetration rate of broadband Internet access among Chinese families is about 3% (in the country as a whole, 3 times higher than ours). True, in the capital and the Moscow region the prevalence of broadband access is quite high (4.4 broadband connections per 100 inhabitants) and is quite comparable to the level in Hungary, Poland or Chile, but the indicators for the rest of Russia are extremely low only 0.4 connections per 100 inhabitants, approximately like in Jamaica or Thailand.

Instead of a conclusion

Let’s look again at the map of world digital communications: let’s not delude ourselves that there are worse places than Russia, but let’s hope for high growth dynamics and expect that our government will have enough sense to direct part of the investment fund’s costs to finance telecommunications projects, and first turn those that will make it possible to level out the digital infrastructure on a nationwide scale and rid it of distortions towards the capital.

In the meantime, even at the Russian post office, public Internet access points are installed in no more than a few thousand post offices. FSUE Russian Post planned, of course, to increase the number of such points to 10 thousand by the end of 2005, but what is ten thousand points on the scale of such a huge country as ours?

In the historical development of communication networks and services, four main stages can be distinguished (Fig. 1). Each stage has its own development logic, relationship with previous and subsequent stages. In addition, each stage depends on the level of economic development and the national characteristics of the individual state.

Figure 1.8 Stages of development of communication networks and services.

The first stage is the construction of a public telephone networkPSTN (Public Switched Telephone Network). The telephone network is the longest, most extensive and accessible telecommunications network. For a long time, each state created its own national analogue public telephone network (PSTN). Telephone communications were provided to the population, institutions, and enterprises and were identified with a single service - the transmission of voice messages. The terminal device of the telephone network was the telephone set, and the computer performed only computing functions. Then, for a long time, the development process followed the path of using public telephone networks to transmit signals from computers, and data transmission began to be carried out over telephone networks using modems. When the exchange of information from computers reached a significant level, it became expedient to create telecommunication networks, which are a set of telecommunications means for delivering information to remote subscribers (users) and means for storing and processing the information to be transmitted. This set also includes software that provides users with the provision of one or more types of services: exchange of voice messages (including traditional telephone communications), data, files, fax messages, video signals, access to various databases, etc. However, even today the telephone remains the main communication service, bringing operating organizations more than 80% of revenues. The installed capacity of the domestic public telephone network exceeds 27 million numbers (planned to reach 40-45 million); in total there are over 800 million telephone sets in the world.

The second stage is the digitalization of the telephone network. To improve the quality of communication services, increase their number, increase control automation and equipment manufacturability, In the early 70s, industrialized countries began work on the digitalization of primary and secondary communication networks. Were created integrated digital networksIDN (Integrated Digital Network) , which also primarily provide telephone services based on digital switching and transmission systems. Currently, in many countries, the digitalization of telephone networks has practically ended.

The third stage is integration of services. Digitalization of communication networks has made it possible not only to improve the quality of services, but also to increase their number based on integration. This is how the concept came about integrated services digital networkISDN (Integrated Service Digital Network). The user of this network is provided with basic access (2B+D), through which information is transmitted over three digital channels: two B channels with a transmission speed of 64 Kbit/s and a D channel with a transmission speed of 16 Kbit/s. Channels B are used for voice and data transmission, channel D is used for signaling and data transmission in packet switching mode. For a user with greater needs, a primary access containing (30B+D) channels can be provided. The ISDN concept is rapidly conquering the telecommunications market, but ISDN equipment is quite expensive, and the list of ISDN services exceeds the needs of the mass user. This is why service integration is beginning to be replaced by the concept of the smart grid.

Stage four - smart networkIN (Intelligent Network). This network is designed to quickly, efficiently and economically provide information services to the mass user. The required service is provided to the user when he needs it and at the time when he needs it. Accordingly, he will pay for the service provided during this period of time. Thus, the speed and efficiency of providing a service makes it possible to ensure its cost-effectiveness, since the user will use the communication channel for a significantly shorter time, which will allow him to reduce costs. This is the fundamental difference between the smart grid and previous networks - the flexibility and cost-effectiveness of service provision.

The state of the Russian telephone network does not meet modern requirements. Half of the telephone exchanges on the PSTN have already fulfilled their depreciation periods and require updating. Therefore, the development of telecommunication networks and services is associated with the re-equipment of automatic telephone exchanges. According to plans for the development of the PSTN, it is planned to put into operation significant numbering capacity in the near future through the installation of new electronic (digital) switching stations and the replacement of outdated automatic telephone exchanges of decade-step and coordinate systems. At the same time, analog switching and channel-forming equipment is also retained on telephone networks. A representative of the new generation of automatic telephone exchanges is the KSM-400 switching station manufactured by Morion OJSC.

And while we are having debates about whether it is worth allocating funds from the investment fund to such infrastructure projects as the construction of interregional digital highways (which, by the way, could serve as a catalyst for the development of other segments of the IT industry and the economy as a whole), all over the world The time is approaching to radically increase the capacity of digital information networks, which will inevitably entail the emergence of qualitatively new types of services that may no longer be available to us.

Unfortunately, such technologies will not reach Russia very soon, because so far, according to the map of world digital communications, our country is not filled with fiber optic lines.

Russian characteristics

with a time-based payment system;
with a subscriber payment system;
with a combined payment system, according to which the meter is turned on after “talking out” a certain amount of time.

In addition, the operator will have the right, in addition to these basic tariffs, to introduce any number of other tariff plans, and the consumer can choose the one that he likes and can afford.

MGTS is the main telephone operator in Moscow, and the subscription fee for individuals is 200 rubles, which is currently slightly higher than the national average. Thus, today the average monthly fee for a fixed-line subscriber in Russia is 160 rubles, while the break-even point for the provision of such a service, according to the Ministry of Information and Communications, is 210 rubles. And if you plan to further expand communication services, then, according to officials, the average monthly fee should be raised to 230-250 rubles, and such an increase will undoubtedly follow in the next two to three years. However, if today the average subscription fee is sharply increased by 50 percent, then fixed-line subscribers will begin to abandon such lines en masse in favor of mobile telephony. Otherwise, fixed-line communications will be almost equal in cost to mobile communications, but with the incomparably greater convenience of the latter. For example, in Moscow, a time-based payment for outgoing calls is expected to be up to 1.8 rubles, which is approximately $0.06, that is, the same amount as a not-so-cheap cellular operator has to pay for 1 minute of an outgoing call on its network. And since the growth of subscription fees in all regions of the country is inevitable, mobile communications are becoming more and more attractive.

If such a law is adopted, it will be another blow to the fixed-line communications system.

IP telephony

IP telephony (or VoIP, Voice over Internet Protocol) is another technological innovation that came to us along with the Internet and indicates that the world will no longer be the same. VoIP is essentially a technology that allows you to reduce the cost of long-distance and international calls by 3-5 times. This happens due to the fact that the main part of the path of the voice signal travels over the Internet in digital form, and this costs much less money and allows you to achieve a higher quality of communication than when using conventional analog lines.

But if in developed countries this situation is considered natural, in other countries it raises serious concerns and, first of all, among monopolistic operators of traditional communications, who see the development of IP telephony as a direct threat to their profits. And, contrary to the laws of the free market, some monopolistic companies are trying to prevent this development, using all the methods available to them. Thus, in Costa Rica, where a single national telephone provider has dominated the market for many years, they are currently trying to regulate the activities of VoIP firms by imposing additional taxes on them as intermediary companies that generate added value. Moreover, it is even proposed to ban the work of VoIP providers altogether, equating their activities to criminal activity. Many Costa Rican experts assess this prospect as catastrophic for the economy of this country, since recently the remote programming (outsourcing) industry has been actively developing in Costa Rica, for which the ability to make cheap international calls is a significant help.

Internet via modem

Thus, in 2005, tariffs of Svyazinvest companies increased by 20-25%, during

The situation is even worse with the penetration of “broadband” into the regions; today there are only 0.9 connections for every 100 residents. According to this indicator, Russia is 10-30 times inferior to South Korea, Japan, the USA, as well as the leading countries of Western Europe, and 4 times inferior to the average of new members of the European Union. Even in China, the penetration rate of broadband Internet access among Chinese families is about 3% (in the country as a whole, 3 times higher than ours). True, in the capital and the Moscow region the prevalence of broadband access is quite high (4.4 broadband connections per 100 inhabitants) and is quite comparable to the level in Hungary, Poland or Chile, but the indicators for the rest of Russia are extremely low only 0.4 connections per 100 inhabitants, approximately like in Jamaica or Thailand.

Instead of a conclusion

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Nizhny Novgorod branch

Electronic written pre-defense

Discipline

Computer Science and Computer Science

Prospects for the development of telecommunication systems in Russia

Graduate's last name

Vasilyeva Elena Alexandrovna

Content

Introduction
Main part
1.2 Wireless
2.3 Satellite communications of the Russian Federation
2.4 Internet
2.5 Cellular communications in Russia
3. Telecommunication networks
3.1 Current trends in the development of telecommunication networks
3.2 Transport layer
3.3 Wireless IP access
Conclusion
Glossary
List of sources used

Introduction

Today, the need for communication, transmission and storage of information is emerging more and more, this is due to the development of human society.

New living conditions make us understand that the information sphere of human activity is a determining factor in the intellectual, economic and defense capabilities of the state and human society as a whole.

The creation of the entire set of material and political conditions in the field of communications led to an explosion in the field of information and a revolution in the way people thought and acted. Currently, people, communicating with each other, through intellectual speech activity, supply the noofield, which is an analogue of the Internet, with morphological linguistic structures that govern life on earth.

RelevancegivenTopics is that for the development of society, it is necessary to introduce innovative systems. This is due to the fact that humanity is moving to a new level of communication and information transfer. Now, in order to transmit a message, there is no need to be at close range. It is possible to transmit information from different parts of the planet. Communication systems have a great impact on all areas of human life. Russia needs to finance the development of communication systems, because the state is one step lower in comparison with global trends. The development of communications at the beginning of the 21st century is characterized by the following concepts: universalization, integration, intellectualization - in terms of technical means and in network terms; globalization, personalization - in terms of services. Progress in the field of communications is based on the development and mastery of new telecommunication technologies, as well as on the further development and improvement of existing ones that have not yet exhausted their potential. Recent years in Russia have not been stable in terms of telecommunications development. They were preceded by the global telecommunications crisis, which led to a slowdown in growth rates. Nevertheless, even during this period, new telecommunication technologies were developed and introduced. During this period, within the framework of OJSC Svyazinvest, the former telecommunication networks were structured in the direction of their consolidation, strong, highly capitalized, profitable and competitive companies were created. As a result, there are seven interregional companies (IRCs) in Russia, and there are about 6,500 registered new operators in the telecommunications market. In June 2003, the State Duma of the Russian Federation adopted a new federal law “On Communications”, which came into force on January 1, 2004. This is essentially related to the completion of one stage in the development of communications in Russia and the beginning of a new stage.

Modernization of terrestrial broadcasting networks through the transition to digital technologies is a global trend, which the Russian Federation also follows. The transition to digital broadcasting in Russia will not only provide the population with multi-program broadcasting of a given quality, but will also have a stimulating effect on the development of the media, communications and production markets of domestic television and radio equipment, the creation of infrastructure for production, implementation, sales and service organizations, the further development of small and medium-sized businesses and the development of competition in this area. The main goal, according to the Concept for the Development of Television and Radio Broadcasting in the Russian Federation for 2008 - 2015, is to provide the population with multi-program broadcasting with a guaranteed provision of publicly accessible television and radio channels of a given quality, which will allow the state to more fully realize constitutional law citizens to receive information.

Objectresearch this graduation qualifying work are telecommunication systems.

Subjectresearch is an analysis of the development of telecommunication systems.

Targetexecution This final qualifying work is to consider the prospects for the development of telecommunication systems.

Main part.

telecommunication cellular satellite

1. History of the development of telecommunications

1.1 Fiber optic communication systems

Development electrical systems transmission of information began with the invention of P.L. Schilling in 1832 telegraph line using needles. Copper wire was used as a communication line. This line provided an information transfer speed of 3 bit/s (1/3 of a letter). The first Morse telegraph line (1844) provided a speed of 5 bit/s (0.5 letters). In 1860, the printing telegraph system was invented. It provided a speed of 10 bit/s (1 letter). Already in 1874, Baudot's six-fold telegraph system provided a transmission speed of 100 bits/s (10 letters). The first telephone lines were built on the basis of the telephone invented by Bell in 1876. They provided an information transmission speed of 1000 bit/s (1kbit/s - 100 letters).

The first telephone circuit used in practice was single-wire with telephone sets connected at its ends Gromakov, Yu.A. Cellular mobile radio communication systems. Technologies of electronic communications / Yu.A. Gromakov. - M.: Eco-Trends, 1994. S-132. . This method required a large number of connecting lines and telephone sets themselves. This device was subsequently replaced in 1878 by a switch, which made it possible to connect several telephone sets through a single switching field. The original grounded single wire circuits used were replaced by two wire transmission lines before 1900. Despite the invention of the switch, each subscriber had his own communication line. Therefore, it was necessary to come up with a way to increase the number of channels without laying additional thousands of kilometers of wires. First commercial system seal was created in the USA. Thanks to this device, a four-channel frequency division system began operating between Baltimore and Pittsburgh in 1918. Most developments have been aimed at increasing the efficiency of sealing systems for overhead lines and multi-pair cables. It was over these two transmission media that almost all telephone circuits were organized before the Second World War.

In 1920, a six to twelve channel transmission system was invented. This increased the speed of information transmission in a given frequency band to 10,000bit/s (10kbit/s - 1000 letters). Upper limit frequencies of air and multi-pair cable lines were 150 and 600 kHz, respectively. The needs of transmitting large volumes of information required the creation of broadband transmission systems.

In the 30-40s of the twentieth century, coaxial cables were introduced into circulation. In 1948, the L1 coaxial cable system was put into operation between cities on the Atlantic and Pacific coasts of the United States. This system made it possible to increase the frequency bandwidth of the linear path to 1.3 MHz, and this ensured the transmission of information over 600 channels.

After World War II, active research began to improve coaxial cable systems. Initially, the coaxial circuits were laid separately, but later they were combined into several coaxial cables in a common protective sheath. For example, the American company Bell developed in the 60s of the twentieth century an intercontinental system with a bandwidth of 17.5 MHz (3600 channels along a coaxial chain or “tube”).

In the USSR, at the same time, the K-3600 system was being developed on the domestic cable KMB 8/6, which has 14 coaxial circuits in one shell. After some time, a coaxial system with a bandwidth of 60 MHz is invented. This provided a capacity of 9,000 channels per pair. 22 pairs are combined in a common shell.

High-capacity coaxial cable systems were used to communicate between two nearby high-density centers. However, the cost of building such systems was high. This was due to the small distance between the intermediate amplifiers and due to the high cost of the cable and its installation. According to modern views, all electromagnetic radiation, including radio waves and visible light, have a dual structure and behave either as a wave-like process in a continuous medium or as a flow of particles called photons, or quanta. Each quantum has a certain energy.

Newton first introduced the concept of light as a flow of particles.A. Einstein, based on Planck's theory, revived new form in 1905, the corpuscular theory of light, which is now commonly called the quantum theory of light. In 1917, he theoretically predicted the phenomenon of stimulated or stimulated radiation. Thanks to this, quantum amplifiers were subsequently created. In 1951, Soviet scientists V.A. Fabrikant, M.M. Vudynsky and F.A. Butaev received a patent for the discovery of the operating principle of an optical amplifier. In 1953, the proposal for a quantum amplifier was made by Weber. In 1954 N.G. Basov and A.M. Prokhorov proposed a theoretically based design of a molecular gas generator. In 1954, independently of them, Gordon, Zeiger and Towns published a report on the creation of a working quantum generator using a beam of ammonia molecules. In 1956, Blombergen established the possibility of constructing a quantum amplifier using solid paramagnetic matter, and in 1957 this amplifier was assembled by Scovel, Feher and Seidel. Quantum generators and amplifiers built before 1960 were called masers. This name comes from the first letters of the English words "Microwave amplification by stimulated emission of radiation", which means "amplification of microwaves using stimulated radiation".

The next stage of development is associated with the transfer of known methods to the optical range. In 1958, Townes and Schawlow theoretically substantiated the possibility of creating an optical quantum generator (OQG) on a solid state. In 1960, Maiman built the first pulsed laser on a solid - ruby. In the same year, the issue of lasers and quantum amplifiers was independently analyzed by N.G. Basov, O.N. Krokhin and Yu.M. Popov Izmailov, Yu.D. Development of the Russian state constellation of communication and broadcasting satellites / Yu.D. Izmailov // Technologies and communications. Satellite communications and broadcasting. - 2008. - S. - 54.

The first gas (helium-neon) generator was created in 1961 by Janavan, Bennett and Herriot. In 1962, the first semiconductor laser was created. Optical quantum generators (OQGs) are called lasers. After the creation of the first masers and lasers, they began to be used in communication systems.

Fiber optics appeared in the early 50s as a new technology direction. At the same time, they began to make thin two-layer fibers from transparent materials (glass, quartz, etc.). By this time, it was proven that if the optical properties of the inner and outer parts of such a fiber are appropriately selected, then a ray of light introduced inside will only propagate along it, reflecting from the shell. Even if the fiber is bent, the beam will still be contained within the core. Thus, a light beam entering optical fiber, is capable of spreading along any curvilinear trajectory. This process is similar to electric current flowing through a metal wire. Therefore, a double-layer optical fiber is often called a light pipe or optical fiber. Glass or quartz fibers are very flexible and thin, but despite this they are strong (stronger than steel threads of the same diameter). The light guides of the 50s were not transparent enough, and with a length of 5-10 m, the light was completely absorbed in them.

In 1966, the idea of using light guides for communication purposes was proposed. Thanks to technical developments, in 1970, ultra-pure quartz fiber was produced, capable of transmitting a light beam over a distance of up to 2 km. In the same year, the rapid development of fiber-optic communications began. New methods for making fibers have emerged; Miniature lasers, photodetectors, optical detachable connectors, etc. are being created.

By 1973-1974 the distance traveled by the beam along the optical fiber reached 20 km, and by the beginning of the 80s 200 km. At the same time, the speed of information transmission via fiber-optic lines has increased by several billion bits/s. It turned out that fiber-optic lines have a number of advantages.

The light signal is not affected by external electromagnetic interference. The signal cannot be eavesdropped or intercepted. Fiber light guides have excellent technical and economic indicators: the materials used have a low specific gravity and do not require heavy metal sheaths; easy to install, install and operate. Fiber light guides, like ordinary electrical wires, can be laid in underground cable ducts, mounted on high-voltage power lines or power networks electric trains, as well as combined with any other communications. Unlike electrical circuits, the characteristics of fiber-optic lines do not depend on their length or on the inclusion or disconnection of additional lines. There are no sparks or short circuits in fiber light guides, which opens up the possibility of using them in explosive and similar industries.

Of great importance in the spread of fiber-optic communication lines is economic factor. At the end of the twentieth century, fiber communication lines had the same cost as wire lines Frolov A.V., Frolov G.V. Local networks of personal computers. - M.: "Dialogue-MEPhI" 2002. S-45. But over time, given the copper shortage, the situation will certainly change. This belief is based on the unlimited raw material resources of quartz, which is the main material of the light guide, while the basis of wire lines are metals such as copper and lead. Currently, optical communication lines dominate all telecommunications systems, ranging from backbone networks to home distribution networks. Thanks to the development of fiber-optic communication lines, multiservice systems are being actively implemented, which make it possible to bring telephony, television and the Internet to the end consumer in one cable.

1.2 Wireless

Paging communication is a radiotelephone communication when messages dictated by the sending subscriber are sent by telephone and received over the radio channel by the recipient subscriber using a pager - a radio receiver with a liquid crystal display. Received messages are displayed on the pager. The essence of paging communication was that the subscriber sends a message to the switchboard, where it is recorded, which is then transmitted to another subscriber. The first pager was developed in 1956 in England. At that time, the number of subscribers could not exceed 57. Pagers contained several customized circuits. These circuits tracked a characteristic sequence of low-frequency signals, upon receiving which the device emitted sound signals. Pagers of this type are called tonal pagers. When receiving a tone signal, the subscriber had to bring the device to his ear and listen to the message that the dispatcher transmitted.

The networks at that time were local in nature and were used mainly by doctors and airport employees. Some similar networks still exist today for the needs of specific services.

By the end of 2000, the number of pager owners in European countries exceeded 20 million.

The history of paging began in the late 1960s back in the USSR. Personal radio calling systems were widely used by individual government agencies. For example, a pager was used in 1980 during the Moscow Olympics. The pager was actively used as a communication tool until cell phones appeared - a means of two-way communication.

Since the advent of cellular communications, pager development has stopped. In big cities, paging companies have closed, giving way to cellular operators. Only in some regions paging communication has been preserved, and the number of clients of paging companies does not exceed one hundred thousand.

Communication is called mobile if the source of information and the recipient move in space. Radio communication is mobile. The first radio stations were intended for communication with moving objects such as ships. The first radio communication device created by A.S. Popov was installed on the battleship "Admiral Apraksin". In those years, wireless communications required bulky transceiver devices. This slowed the spread of personal radio communications even in the Armed Forces, not to mention private customers. On June 17, 1946, in St. Louis, USA, Southwestern Bell launched the first radiotelephone network for private customers and immediately became a leader in the telephone business. The equipment was based on tube electronic devices; because of this, the equipment was very bulky and was installed only in cars. But despite this apparent inconvenience, the number of mobile communications users grew rapidly. This in turn created a new problem. Radio stations operating on channels close in frequency interfered with each other. This significantly deteriorated the quality of communication. For mass implementation it was necessary to solve this problem.

In 1947, the transistor was invented, replacing vacuum tubes and having a significantly smaller size. This was of great importance for the further development of radiotelephone communications and created the preconditions for the widespread introduction of mobile phones. But it was possible to reduce the influence of mutual interference only by changing the principle of communication organization. Moore, M. Telecommunications M. Moore, T. Pritsky, K. Riggs, P. Southwick. - St. Petersburg: BHV-Petersburg, 2005. S-90

In the 40s of the last century, thanks to the study of the ultrashort wave range, it was possible to establish its main advantage over short waves - wide range. But there was also a serious drawback - strong absorption of radio waves by the propagation medium. Ultrashort radio waves are not able to bend earth's surface, therefore, communication was provided only on the line of sight, and even with a powerful transmitter, the communication range reached only 40 km. It was this flaw that D. Ring, an employee of the American company Bell Laboratories, used in 1947. He proposed a new idea for organizing communications. It consisted of dividing space into small areas - cells with a radius of 1-5 kilometers and separating radio communications within one cell from communications between cells. Repeating frequencies allowed us to solve the problem of using the frequency resource. This made it possible to use the same frequencies in different cells distributed in space. This design looked like this: in the center of a separate cell there was a basic receiving and transmitting radio station, which provided radio communication within the cell with all subscribers. The cell size was determined by the maximum communication range of the radiotelephone device with the base station. The maximum radius is called the cell radius. During a conversation, the cellular radiotelephone is connected to the base station by a radio channel through which the telephone conversation is transmitted. Subscribers communicate with each other through base stations, which are connected to each other and to the public telephone network.

To ensure uninterrupted communication when a subscriber moves from one zone to another, it was necessary to use computer control over the telephone signal emitted by the subscriber. It was computer control that made it possible to switch a mobile phone from one intermediate transmitter to another within just a thousandth of a second. Thus, the central part of the mobile communication system are computers that find a subscriber located in any of the cells and connect him to the telephone network. The practical use of cellular communications became possible only after the invention of microprocessors and integrated semiconductor chips, because Computer technology was still at such a level that its commercial use in telephone communication systems was difficult.

First cellular telephone prototype modern apparatus designed by Martin Cooper (Motorola, USA) in 1973.

In 1983, a network of the AMPS (Advanced Mobile Phone Service) standard, which was developed by Bell Laboratories, was launched in Chicago. In 1985, in England, the TACS (Total Access Communications System) standard was adopted, which was a variation of the American AMPS. Two years later, due to the sharply increased number of subscribers, the HTACS (Enhanced TACS) standard was adopted, adding new frequencies and partially correcting the shortcomings of its predecessor. France stood apart from everyone else and began using its own Radiocom-2000 standard in 1985. The next standard was NMT-900, using frequencies of the 900 MHz range. The new version came into use in 1986. It allowed to increase the number of subscribers and improve the stability of the system. By the end of the 1980s, the creation of the second generation of cellular communication systems began, based on digital signal processing methods.

In 1982, the European Conference of Postal and Telecommunications Administrations (CEPT) created a group called Groupe Special Mobile, the purpose of which was to develop a single European standard for digital cellular communications. But it was only eight years later that the specifications for the standard were proposed. Having calculated the prospects for the development of cellular communications in Europe and throughout the world, it was decided to allocate the 1800 MHz range for the new standard. This standard is called GSM - Global System for Mobile Communications. GSM 1800 MHz is also called DCS-1800 (Digital Cellular System 1800). The GSM standard is a digital cellular communication standard. It implements time division of channels (TDMA - time division multiple access, message encryption, block coding, as well as GMSK modulation) (Gaussian Minimum Shift Keying). Rice L. Experiments with local networks: Transl. from English - M.: Mir, 1999. - 268s.

Peskova, S.A. Networks and telecommunications - M., Academy Publishing House, 2007. S-143 In the late 90s, due to the development of the Internet, many cellular users wanted to use their phones as modems, and the existing speeds were not enough for this. To keep up with the demand of their customers for access to the Internet, engineers invent the WAP protocol. WAP is an abbreviation for Wireless Application Protocol, which translates to Wireless Application Protocol. In principle, WAP is a simplified version of the standard Internet protocol HTTP, adapted to the limited resources of mobile phones. But this protocol does not allow viewing standard Internet pages; they must be written in WML. Therefore, cellular network subscribers received very limited access to Internet resources. Another inconvenience was that to access WAP sites, the same communication channel was used as for voice transmission, that is, while you are loading or viewing a page, the communication channel is busy, and the same money is debited from your personal account as during a conversation.

Manufacturers of cellular equipment urgently had to look for ways to increase data transfer speeds. As a result of this research, HSCSD (High-Speed Circuit Switched Data) technology was born, providing speeds of up to 43 kilobits per second. With the advent of GPRS, the WAP protocol began to be used again, since access to small-volume WAP pages becomes many times cheaper than in the days of CSD and HSCSD. Now many telecom operators provide unlimited access to WAP network resources for a small monthly subscription fee.

With the advent of GPRS, cellular networks ceased to be called second generation networks - 2G. This is how the cell phone, computer and Internet merged. Developers and operators are offering us more and more new additional services. Using the capabilities of GPRS, a new message transmission format was created, which was called MMS (Multimedia Messaging Service). It allows you to send not only text, but also various multimedia information from your cell phone, for example, sound recordings, photographs and even video clips. Moreover, an MMS message can be sent either to another phone that supports this format or to email. As the power of phone processors increases, it becomes possible to download and run various programs on it. The main language for writing them is Java2ME. Owners of most modern phones now have no difficulty connecting to the website of Java2ME application developers and downloading, for example, a new game or other necessary program to their phone. Also, no one will be surprised by the ability to connect the phone to a personal computer in order to, using special software, most often supplied with the handset, save or edit an address book or organizer on a PC; while on the road, using a mobile phone + laptop combination, access the full Internet and view your email. However, our needs are constantly growing, the volume of transmitted information is growing almost daily. And more and more demands are being placed on cell phones, as a result of which the resources of current technologies are becoming insufficient to satisfy our increasing demands.

It is precisely to solve these requests that the recently created third-generation 3G networks are designed, in which data transmission dominates over voice services. 3G is not a communication standard, but a general name for all high-speed cellular networks that will grow and are already growing beyond the existing ones. Huge data transfer rates allow you to transfer high-quality video images directly to your phone and maintain a constant connection to the Internet and local networks. The use of new, improved security systems makes it possible today to use a telephone for various financial transactions - a mobile phone is quite capable of replacing a credit card.

It is quite natural that third generation networks will not become the final stage in the development of cellular communications - as they say, progress is inexorable. Current integration various types communications (cellular, satellite, television, etc.), the emergence of hybrid devices, including a cell phone, PDA, video camera, will certainly lead to the emergence of 4G, 5G networks. And even science fiction writers today are unlikely to be able to tell how this evolutionary development will end.

Globally, there are currently about 2 billion mobile phones in use, of which more than two-thirds are connected to the GSM standard. The second most popular is CDMA, while the rest represent specific standards used mainly in Asia. Now in developed countries there is a situation of “saturation”, when demand stops growing.

2. Main directions in the development of telecommunications

2.1 Prospects for the development of digital television

Standard Russian television has long been outdated. It broadcasts in the Secam standard and provides 25 frames per second with interlaced image scanning. The number of points in this format is 720×576. Other countries broadcast in different versions of PAL formats, differing from Secam only in the way they encode color.

The most developed countries in the technical field of television are: Japan, Mexico, Canada, South Korea, Taiwan, the USA and even Honduras. They broadcast in the modern NTSC 3.58 standard. The NTSC 3.58 standard gives 29.97 frames per second, while the number of vertical lines is reduced from 576 to 480.

Five to ten years ago they began to develop a new television standard, HDTV. Translation of the abbreviation HDTV means High Definition Television into Russian - high definition television.

The resolution of a regular TV is 720×480 or 345,600 pixels. The developers of the HDTV format have achieved a resolution of 1920×1080 or 2 million pixels. In this case, the image is not simply transmitted frame by frame, but the frames seem to be partially superimposed on each other, which further enhances the effect of image clarity. And there is every reason to say that in a year or two most channels will be broadcast in HD format. Cable television does not yet broadcast an HD signal, but it is obvious that competition from satellite television companies will force cable providers to come to HDTV.

HD television receivers are divided into two types. These are the so-called HDTV Upgradeable and HDTV Built-in. Built-in HD TVs have a built-in Through-the-air receiver. This allows you to receive HD transmissions using a regular indoor or outdoor antenna.

All HD TVs, with rare exceptions, have PIP (Picture-in-Picture) - a device that allows you to simultaneously watch two or more TV channels. Therefore, those who can purchase an HDTV with a Built-in receiver can, having a satellite dish and an HDTV receiver, watch simultaneously in HD format both satellite television programs and VHF channel programs. Rice L. Experiments with local networks: Transl. from English - M.: Mir, 1999. S-45.

Nowadays, almost every home has a DVD player. But unfortunately, even on HD TVs it is not yet possible to get HD image quality when watching DVD videos. However, a DVD player that has the Progressive Scan function allows you to get a resolution of 1280×1080=1,382,400 pixels, which is very high and almost approaching HD, while without Progressive Scan the viewer gets only 960×720=691,200 pixels. Such discs are called HDCD. One DVD disc holds 2 - 4 hours of video in Mpeg 2 format with a frame size of 720×576 for PAL and 720×480 for NTSC and with 6-channel audio quality of 64 Kbps per channel (this is very small). The HD format provides an Mpeg 2 video stream speed of 28.8 Mbit/s, which is 3-4 times higher than DVD. There is no such large information carrier today. More recently they released laser discs called Blue-Ray, which hold about 24 GB. These discs, unlike regular ones, are read with a blue laser, hence the corresponding name. Russian manufacturers have already presented at the information technology exhibition in Brussels CeiBT the latest optical disk based on a ferromagnet, which can hold 1 TB (that’s 1000 GB, that is, about 212 DVD disks), the dimensions of which are only 13 cm in diameter and 2 mm in thickness.

2.2 Current state and prospects for the development of cable systems

The most common guide systems today are symmetrical cables. The main feature of symmetrical cables is the presence of circuits that consist of two conductors that have the same structural and electrical properties. Cables are used to transmit electromagnetic energy in the frequency range 0-1 GHz. Symmetrical communication cables began to be used in the field of subscriber access. This has become relevant due to the fact that users of telephone and computer networks require inexpensive high-speed access to the Internet. Telecom operators began to use equipment based on xDSL technology to provide customers with a wide range of services. xDSL technologies make it possible to increase the speed of data exchange over city telephone network cables to 56 Mbit/s. But a regular telephone cable is not suitable for this, since it does not allow achieving 100% compaction. This happens because there are pairs in the cable that do not meet the requirements of modern digital transmission systems in terms of mutual noise immunity.

The TP brand cable is the most commonly used today. After 1995, there were changes in the construction of cable communication systems significant changes. Now during construction they have stopped using cables with 0.32 mm cores. The main volume of cables falls on the production of cables with 0.4/0.5/0.7 mm cores. This is due to the fact that during construction in cities, spot development is carried out and the length of subscriber lines increases. The insulated cores in the cable are usually twisted into pairs or quads with a pitch of no more than 100 mm, and in a quad, two cores located diagonally form a working pair. The number of pairs from 5 to 2400 is determined depending on the cable brand.

Cables for rural telephone networks are intended for interstation network lines and subscriber communications. They are used in time division transmission systems with pulse code modulation and providing a speed of 2.048 Mbit/s at a constant remote supply voltage of up to 500 V. The following brands of cables are produced in Russia: KSPP, KSPPB, KSPZP, KSPZPB. Conducting copper conductors with a diameter of 0.9 and 1.2 mm are insulated with polyethylene with a thickness of 0.7 and 0.8 mm, respectively, with a tolerance of 0.1 mm. Four insulated cores are twisted into a quadruple with a pitch of 150 and 170 mm. Two cores located diagonally form a working pair.

Low-frequency long-distance symmetrical cables are used on relatively short connecting lines, as well as for the installation of cable inputs and inserts into overhead lines, including with circuits compacted in the spectrum up to 150 kHz, as well as for the installation of connecting lines of automatic telephone exchanges and between automatic telephone exchanges and MTS.

Symmetrical low-frequency cables have conductive cores with a diameter of 0.9 and 1.2 mm, a diameter over insulation of 1.9 and 2.4 mm. Four cores are twisted into a four around a polyethylene cord - filler with a pitch of no more than 300 mm. Low-frequency cables, depending on the brand, are intended for installation in telephone sewers, sewers, tunnels, mines, over bridges and in soft stable soils without increased electromagnetic influence and the danger of damage by rodents or directly in soils of all categories that are not aggressive to steel armor and are not susceptible to frost damage deformations.

Long-distance high-frequency (HF) cables are designed for operation on main lines, in intrazonal primary networks and trunk lines of city telephone networks (TTN). Currently, these RF cables are used both in analog transmission systems of the K-60 type, and in digital transmission systems with speeds of 8448 kbit/s and 34368 kbit/s, or in analog transmission systems in the frequency range up to 5 MHz, operating at AC voltage remote power supply up to 960 V or constant voltage up to 1000 V. The conductive cores of the cables are made of copper wire with a diameter of 1.2 mm, wrapped with colored polystyrene thread (cordel) with a diameter of 0.8 mm and polystyrene tape 0.045 mm thick, applied with overlap to the side, opposite to the direction of winding thread. Four cores with insulation of different colors are twisted into a quadruple with a round polystyrene thread filled in the center and wrapped with colored cotton or synthetic yarn or tape. The steps for twisting insulated cores into fours are different and do not exceed 300 mm.

Today, city telephone cables such as TPP, TPPep, TPppZP, TPPep-NDG in terms of production volume remain one of the leading positions in the cable products market, although there is a trend towards a decrease in demand for them, since the products’ properties do not meet the requirements of the modern market information technologies. Therefore, the share of copper cable use in communication networks will decrease due to the use of fiber optic and wireless technologies.

The use of optical and copper cables is gradually being established in a certain proportion: optical - in the main sections, copper - closer to subscribers. According to experts, this trend will remain for 10-15 years.

2.3 Satellite communications of the Russian Federation

As part of the new Federal Space Program of Russia, until 2015, RSKS is constructing and launching new spacecraft. The system is based on three satellites of the Express-RV series. The service life of the system is 15 years. In addition to telecommunications services, satellites will help ensure the transmission of service information (map, weather, differential corrections, GLONASS and GPS). The new composition of satellites ensures mutual redundancy of spacecraft throughout the entire orbital arc. This guarantees the development and operation of satellite communication and television and radio broadcasting systems in the interests of government users throughout our country. Moore, M. Telecommunications M. Moore, T. Pritsky, K. Riggs, P. Southwick. - St. Petersburg: BHV-Petersburg, 2005С-78

The development of the satellite communication network is characterized by the frequency resource of the Russian satellite constellation. It includes the most significant for Russian market satellites. The group has an international registration under the name "Satellite networks "Express". The frequency resource of the communication satellites "Horizon" (and their analogue - the first series of spacecraft (SC) "Express") is not taken into account, since these satellites operate beyond the guaranteed period services.

By 2007, RSCC had completely transferred all broadcast television and radio programs from analogue to digital technologies. Through GPKS satellites, television and radio broadcasting programs are distributed to five broadcast zones, taking into account the time shift. The package of all-Russian programs is available throughout Russia, and international versions of the programs are also available in the countries of the Asia-Pacific and Atlantic regions.

In accordance with the state program for the development of digital television and radio broadcasting in Russia until 2015, RSCC is commissioning a new center for compressing television and radio program signals. The stream is broadcast in the DVB-S2 standard and according to the MPEG-4 part 10 standard. Currently, the formation and delivery of all-Russian television and radio program packages to satellites is carried out in the MPEG-2/DVB-S standard. With this standard, the transponder contains only 8 standard quality programs. The MPEG-4 standard in combination with DVB-S2 makes it possible to transmit up to 20 standard quality programs or 10 high quality television programs in one transponder. The introduction of the MPEG-4 standard will create conditions for the transition to television programs of a new quality - high-definition television (HDTV). This will subsequently make it possible to directly broadcast television from a satellite to mobile terminals of end users, including in interactive mode.

The satellites created by RSCC will have transponders with increased energy for the development of television. They should help solve various problems in building television and radio broadcasting networks, including the evolution of mobile television. The configuration of the new spacecraft includes three retargetable antennas: one is C-band, the other two are Ku-band. Thanks to the improvement in the energy characteristics of the new satellites by 3-5 dB, compared to the operating Express-AM spacecraft, it will be possible to use ground-based antennas about a meter in diameter. All this will allow GCPS to quickly respond to rapidly changing market needs and enter untapped regions.

Terrestrial satellite network operators are divided into three main categories: interactive VSAT network operators; point-to-point network operators; operators of large corporate networks. The development of interactive VSAT network operators began in 2003 thanks to the use of new VSAT technologies such as DVB-RCS.

Point-to-point network operators emerged in the 1990s. These companies were often created by large operators that controlled public terrestrial networks. But the most dynamically developing operators are the operators of interactive VSAT networks, which own the central stations of these networks (HUB). From 2003 to 2008, at least 20 central stations were built in Russia. Multiservice services are based on promising IPTV technology. The main factor in its development was the presence of a large number of central stations of interactive VSAT networks and the fact that this service can be provided via low-speed communication channels, of which the vast majority are in Russia.

Thus, the development of the satellite communications network in Russia is based on expanding the satellite constellation and improving signal processing methods not only at central ground stations, but also directly on spacecraft. Thus, satellite, both fixed and mobile satellite multiservice communications, can occupy a significant share of the market for information and telecommunication services.

2.4 Internet

The most popular direction in the development of the World Wide Web is the creation of a semantic web. The Semantic Web is a superstructure on top of the World Wide Web that makes information posted online understandable to computers. The Semantic Web is a concept in which every human word is described in a language that a computer can understand. Thanks to the Semantic Web, structured information is available for any application. Programs use resources regardless of platform and programming language. Programs will be able to process information, as well as draw conclusions and make decisions. If widely adopted and used wisely, it could revolutionize the Internet. The Semantic Web uses the RDF (Resource Description Framework) format, which is based on XML syntax and uses URIs to identify resources. It is used to make the described resource understandable to the computer. We also introduced a new query language for faster access to RDF data - these are RDFS (English RDF Schema) and SPARQL (English Protocol And RDF Query Language) (read “spamrkl”).

Currently, the World Wide Web is developing in two directions: semantic and social web. The Semantic Web improves the coherence and understanding of information on the World Wide Web by introducing new metadata formats. The Social Web organizes information supplied by the Web users themselves.

One of the outstanding discoveries in the field of communications was Internet telephony. The beginning of its inception is considered to be February 15, 1995. On this day, VocalTec launched its first soft-phone, a program for exchanging audio messages over an IP network. In October 1996, Microsoft launched the first version of NetMeeting. And already in 1997, telephone connections via the Internet became quite common for people located in different parts of the planet.

How does regular long-distance and international telephone communication differ from Internet telephony? During a conversation, the subscriber occupies an entire communication channel, regardless of whether he speaks or is silent. This happens when voice is transmitted over the telephone using the usual analog method.

During the digital method, information can be transmitted in separate "packets". Thanks to this, one communication channel can be used to send information simultaneously from many subscribers. This temporary “packet compaction” makes it possible to use existing communication channels much more efficiently and “compress” them. At one end of the communication channel, information is divided into packets, each of which, like a letter, is equipped with its own individual address. Over a communication channel, packets from many subscribers are transmitted “interspersed”. At the other end of the communication channel, packets with the same address are again combined and sent to their destination. This packet principle is widely used on the Internet.

By connecting a microphone and headphones to a personal computer, the user can use Internet telephony to call any subscriber who has a landline telephone. In this case, payment will be charged only for using the Internet. Before using Internet telephony, the subscriber needs to install a special program on his computer.

You can use Internet telephony even without a personal computer. It is enough to connect a regular landline telephone with tone dialing. When dialing a number, each dialed digit goes into the line in the form of alternating currents of different frequencies. Almost any modern telephone is equipped with this tone mode. To use Internet telephony using a telephone, you need to purchase a credit card and call the central server computer at the number indicated on the card. After that, the server machine gives voice commands: use the telephone buttons to dial the serial number and card key, as well as the country code and telephone number of your interlocutor. When talking, the server turns analog signal into digital, sends it to another city, to a server located there, which again converts the digital signal into analog and sends it to the desired subscriber. In this case, subscribers talk as if on a regular telephone.

In 2003, Skype was launched. It is very easy to install and use, and is completely free. The program allows you not only to talk, but also to see your interlocutors who are at their computers in different parts of the world. In order to have a video image of the interlocutors during a conversation, the computer of each of them must be equipped with a web camera. This type of communication allows two people located anywhere on our planet to communicate almost instantly. At the same time, despite the different distances, subscribers create a feeling of personal communication.

2.5 Cellular communications in Russia

The first cellular network in Russia appeared in 1991, when Delta Telecom began its work in the analog NMT-450i standard.

During this time, various companies operating in our country used all cellular communication standards. The most used product that these networks sold was voice traffic - little thought was given to SMS or additional infotainment services, and there were neither high-speed protocols for high-speed data transfer nor the desire to buy the appropriate equipment.

Due to the August 1998 crisis, operators lost many customers, which shook the economics of cellular companies. To save themselves from ruin, all mobile operators began developing projects for consumers with low incomes. The first among them was VimpelCom, which in the fall of 1999 offered an inexpensive service package called Bi+.

In 2000, MTS and VimpelCom were the first to use WAP service in their networks. Using the WAP service, subscribers could download data from special WAP sites located on the Internet using their cell phone. The information was the same as on WEB sites, but adapted for the small screens of cell phones. In the period from 2000 to 2005, two development trends can be distinguished. Firstly, GSM companies began to develop throughout Russia.

Secondly, mobile operators began to actively fight for corporate subscribers. Operators organized special departments that attracted large users with discounts, additional payment benefits, an individual set of services, as well as data transfer services using GPRS technology. The SkyLink operator was founded in July 2003 to consolidate regional NMT-450 operators and implement a project to create a unified federal cellular network of the IMT-MC-450 standard (CDMA2000 1X technology). SkyLink uses high-speed data transmission technology EV-DO (on average 9-10 times faster than GPRS). Thanks to this, corporate clients who have a real need to organize and use a mobile office wirelessly become its clients.

Today, mobile communications cover a huge number of subscribers - according to Euroset analysts, who determine this indicator by the number of sales of mobile terminals, this is about 70% of the country's population, and according to IKS-Consulting and J`son&Partners, which use the number of SIM cards sold - 100%. However, operators see their further development in the construction of next generation networks (3G) - they are designed to provide higher data transfer speeds than EDGE can. The future, according to analysts, lies in additional services (video calls and transmission of “heavy” content - films, video surveillance results, high-quality sound in mp3 format, etc.), since voice transmission, as a dominant service, is gradually beginning to lose weight - earn In this segment, everything is more difficult for operators.

VimpelCom and other Big Three cellular operators received licenses for 3G cellular services in 2007, including Moscow and the Moscow region. However, operators cannot begin to deploy these networks in Moscow until the Ministry of Defense has agreed on the release or sharing of radio frequencies in the 2.1 GHz range, which, among other things, are used in air defense systems.

The procedure for issuing permits for the use of radio frequencies requires improvement, according to experts preparing changes to the 2020 strategy. “Today, due to inconsistency in the work of regulators, it takes an operator an average of one year to obtain permission to use radio frequencies. At the same time, the installation of one base station<. >on average, it is carried out in two months." To solve this problem, experts propose transferring the EMC examination and the assignment of frequency ratings to the Ministry of Telecom and Mass Communications.

“To follow global trends in the development of the industry, it is necessary to pursue a policy of technological neutrality in the use of the radio frequency spectrum,” experts write and propose to amend the Law “On Communications” accordingly. They also propose to amend the Law “On Communications” so that the license obtained at the auction already gives the right to use radio frequencies, and to expand the grounds for holding auctions. In April 2011, the government approved an action plan to reduce excessive government regulation in the communications industry. According to it, in the first quarter of 2012, changes should be made to the table of distribution of frequency bands in Russia, which will divide the joint use bands into bands of predominantly civil and government use. In this regard, big battles with the military department are ahead, says a source close to the SCRF. According to him, the military has already stated that they want to get 90% of these bands, but the Ministry of Communications will insist that the bands used by the Ministry of Defense for communications, and not for direct military needs, such as radar, be transferred to the civilian band.

Prospects for the development of communications and information technologies. MCS - message switching center

Russian characteristics

IP telephony

Internet via modem

Instead of a conclusion

Russian characteristics

IP telephony

Internet via modem

Instead of a conclusion

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Introduction

Today, the need for communication, transmission and storage of information is emerging more and more, this is due to the development of human society.

New living conditions make us understand that the information sphere of human activity is a determining factor in the intellectual, economic and defense capabilities of the state and human society as a whole.

Objectresearch this graduation qualifying work are telecommunication systems.

Subjectresearch is an analysis of the development of telecommunication systems.

Targetexecution This final qualifying work is to consider the prospects for the development of telecommunication systems.

Main part.

1. History of the development of telecommunications

1.1 Fiber optic communication systems

The first gas (helium-neon) generator was created in 1961 by Janavan, Bennett and Herriot. In 1962, the first semiconductor laser was created. Optical quantum generators (OQGs) are called lasers. After the creation of the first masers and lasers, they began to be used in communication systems.

1.2 Wireless

The networks at that time were local in nature and were used mainly by doctors and airport employees. Some similar networks still exist today for the needs of specific services.

By the end of 2000, the number of pager owners in European countries exceeded 20 million.

Since the advent of cellular communications, pager development has stopped. In big cities, paging companies have closed, giving way to cellular operators. Only in some regions paging communication has been preserved, and the number of clients of paging companies does not exceed one hundred thousand.

First cellular telephone prototype modern apparatus designed by Martin Cooper (Motorola, USA) in 1973.

2. Main directions in the development of telecommunications

2.1 Prospects for the development of digital television

Five to ten years ago they began to develop a new television standard, HDTV. Translation of the abbreviation HDTV means High Definition Television into Russian - high definition television.

HD television receivers are divided into two types. These are the so-called HDTV Upgradeable and HDTV Built-in. Built-in HD TVs have a built-in Through-the-air receiver. This allows you to receive HD transmissions using a regular indoor or outdoor antenna.

2.2 Current state and prospects for the development of cable systems

The use of optical and copper cables is gradually being established in a certain proportion: optical - in the main sections, copper - closer to subscribers. According to experts, this trend will remain for 10-15 years.

2.3 Satellite communications of the Russian Federation

2.4 Internet

Currently, the World Wide Web is developing in two directions: semantic and social web. The Semantic Web improves the coherence and understanding of information on the World Wide Web by introducing new metadata formats. The Social Web organizes information supplied by the Web users themselves.

2.5 Cellular communications in Russia

The first cellular network in Russia appeared in 1991, when Delta Telecom began its work in the analog NMT-450i standard.

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