Nowadays, you can often hear about the CDMA standard. What is this standard and where did it start its development? CDMA (Code Division Multiple Access) is a code division multiple access technology that was invented and developed for military purposes. After World War II, the technology was used both in the USSR and in the USA in military communication systems.

Communication was used to exchange information between military aircraft and ground services. But over time, this technology began to be used for civilian purposes. CDMA technology very quickly began to spread throughout the entire planet Earth. America has conducted a number of checks and tests on this link, which have shown high results in comparison with other standards. Mass production of CDMA equipment began. CDMA technology continues to strengthen its position in different countries. She gained immense popularity in the USA, Japan and South Korea. Now CDMA covers all continents with over 150 million subscribers. This is because the standard has tremendous advantages.

The CDMA standard has a higher quality of communication and is safe for human health. The impact of electromagnetic radiation on the human body is 2 times less than in other standards, since the terminals require minimum power consumption for operation, and therefore the output power does not harm health in any way. And a special built-in encryption algorithm provides protection against unauthorized eavesdropping.

If the CDMA standard is really so unique and secure, how long will the GSM standard last on the market? So you can't tell right away, something global should happen that will completely change the situation on the communications market. Today CDMA and GSM divide the market into two camps. GSM is trying to keep up with CDMA by coming up with new technologies. For example, such as EDGE, with the help of which it is possible to increase the data transfer speed up to 384 Kb per second. But all the same, no matter how GSM develops, CDMA rises several steps up, for example, releasing CDMA / EV-DO Rev. B +, in which the data transfer rate is up to 14.7 Mbps.

CDMA uses a wideband signal for data transmission. The same frequency can be used throughout the network, which means that more frequency bands are used than are needed for normal messaging. A large group of users use the same frequency band at the same time, in contrast to the GSM standard, in which a frequency channel is provided to each user for a certain period of time. And in order not to interfere with each other, nearby base stations are forced to use different channels. And in the GSM standard there are seven times less of them than in this network. Therefore, in densely populated areas, there is a great need to use a large number of base stations.

CDMA uses Soft Handoff technology, that is, when a subscriber moves from one base station to another, there are no disruptions in sessions, which can be observed in other standards. If the subscriber is on the border of two or more base stations, the device connects him with all the nearest base stations and those that have the best signal continue to guide the subscriber, who does not even suspect that he was switched from one base station to another.

Let's hope that the development of the CDMA standard will not stop there, and will delight us with its new implementations in the technology, open up great prospects for the future and become the world leader in the communications market!

CDMA - Code Division Multiple Access is a subset of cellular communication standards, the main difference of which from other standards is the principle of organizing multiple access of subscribers to one base station.

Mobile operators have always faced two main problems:

Constant increase in the subscriber base;

Ensuring communication security.

It was the solution of these two problems that caused the improvement of cellular communication standards, as well as the emergence of new ones.

Today, there are three main methods of organizing cellular communications:

1. FDMA - Frequency Division Multiple Access - frequency division multiple access - cellular standards, in which a certain frequency range is allocated to each subscriber. The most famous FDMA technology standards:

AMPS - Advanced Mobile Phone Service - an improved mobile phone service - an analog standard with a frequency range of 30 kHz.

DAMPS - (Digital) digital implementation of the AMPS standard;

NAMPS - (Narrow-band) AMPS with a reduced frequency range of 10 kHz - allows you to increase the cell capacity.

TACS - Total Access Communication System - communication system of general access - channel width 25 kHz.

2. TDMA - Time Division Multiple Access - time division multiple access. In contrast to the frequency method, time division allows several subscribers to use the same frequency range, while the transmission of signals between them and the base station is time-sliced. The most famous TDMA technology standards:

IS-54 is an extension of the AMPS standard - 30 kHz frequency channels are divided into three time slots.

PDC - 25 kHz channels with three timeslots each.

GSM - Global System for Mobile communications - 200 kHz band with 8 time slots.

3. CDMA. Unlike the first two methods, the code division method allows all subscribers to work in the same frequency range. Moreover, such a range in CDMA is much wider than in the first two methods. So, in the most common CDMA implementation - IS-95, the bandwidth is 1.25 MHz. The latest third generation (3G) CDMA communication standard, CDMA2000, uses the same bandwidth.

In cellular communications, the CDMA method was used relatively recently - the first CDMA operator appeared in 1995. Prior to this, the method of code separation was widely used in communications by the military.

Main advantages

High noise immunity.

Due to special coding and "smearing" of the signal (see Organization of multiple access) over the frequency range, a high level of protection of useful information from accidental (or intentional) interference is achieved. Even with a partial loss of information from narrowband interference, the information transmitted in the rest of the signal will be sufficient to restore the original high quality analog signal.

Large cell capacity.

Cell capacity depends on the "independence" of the codes used by subscriber units when coding information for communication within one cell. The more codes there are, the lower their "independence" and, thus, the more mutual interference.

A large cell capacity is also ensured by the fact that all cells operate on the same frequency, so that there is no need to specifically allocate frequencies to cells (as is required in FDMA and TDMA - neighboring cells must operate at different frequencies).

Safety.

Communication security in the CDMA standard is ensured, firstly, using a very complex radio interface, which uses six channels to transmit data and control information. Secondly, the use of a noise-like signal (NLS) for transmitting information through the radio interface makes it quite difficult to intercept, and the use of a unique coding sequence in conjunction with data encryption ensures data security from decryption.

With a specific implementation of the CDMA method in cellular communication standards, subscribers are protected from "hooking". So in the IS-95 standard, such protection against unauthorized use of their account is provided by the AKEY mechanism - an eight byte key stored in a cell phone and which is a unique identifier for each subscriber. It is entered into the machine at the time of sale and is also stored in the operator's database.

Besides security from the point of view of information protection, CDMA is also safe for the health of subscribers. Due to the low intensity signal, the total level of electromagnetic radiation is much lower than in other standards such as GSM, AMPS.

Flaws

Today we can say that CDMA has no shortcomings. As a technology, CDMA is already well established. There are several standards based on it, for which there are several manufacturers that provide the entire necessary range of hardware - base stations, cell phones.

Organization of multiple access

Picture 1
Signal spread spectrum

In fig. 1 shows the principle of spreading the spectrum of a useful signal (top graph) - voice information into a CDMA signal - a broadband noise-like signal.

Multiple access in CDMA is realized through special signal coding. The analog voice signal is converted into digital packets, which are then passed through a Walsh sequence (64 or more codes). The transform function also uses a pseudo-random number (one of 2199023255551 numbers) that is unique for each subscriber within the cell. The result is a broadband signal with a frequency range of 1.23 MHz, which is transmitted via the radio interface.

CDMA2000

CDMA2000 is the latest third generation (3G) cellular communication standard based on the CDMA method. Currently, a fully functional CDMA2000 network in commercial operation is available only in Japan (cellular operator DOCOMO).

In its capabilities, CDMA2000 surpasses the CDMA standard IS-95 in many respects, which is called CDMAOne in the new context.

So, CDMA2000 allows data transmission at speeds up to 2 Mbps, which is quite enough for real-time video transmission.

CDMA2000 is fully compatible with CDMAOne, which provides an easy and inexpensive migration of mobile operators to the new standard.

CDMA in Russia

The situation with CDMA in Russia was unsuccessful from the very beginning of its appearance. Having affected the interests of several influential structures at once, CDMA encountered resistance from the Ministry of Communications and security agencies. The fact is that for synchronization with CDMA mobile communication, GPS is used - the Global Positioning System - the Global Positioning System based on the use of satellites that are not at all Russian-made - it simply could not be left out. And CDMAOne in Russia lost its GPS, and with it its mobility.

Under the license of the Ministry of Communications and the State Communications Committee, cellular operators were allowed to use only CDMA networks with fixed subscribers operating at 800 MHz.

Over the course of 3 years since the first CDMA networks appeared in Russia - 1998-2001 - operators have not managed to win back CDMA mobile communications.

Beginning in 2001, MCC (Moscow Cellular Systems), and at the beginning of this year in St. Petersburg (Delta Telecom), began deploying a CDMA2000 network, so far only in a test version. The frequency range that was provided for CDMA2000 is 450 MHz. Most importantly, a permit issued by the State Commission on Radio Frequencies (SCRF) allows the deployment of mobile (read mobile) radio communication networks.

Telephones

Today the choice of cell phones with CDMA2000 support is not so great. On the Russian market there are mainly devices from the Korean company Samsung: SCH X120, X130, X230, X250, X350, X420 (see table 1).

Additional Information

http://www.minsvyaz.ru - Site of the Ministry of Communications of the Russian Federation.

http://www.sotovik.ru - Cellular news.

http://www.cdma.ru - CDMA in Russia.

CDMA - Code Division Multiple Access - code division multiple access system.

CDMA or cdmaOne is an all-digital standard using the frequency range 824-849 MHz for reception and 874-899 MHz for transmission.

CDMA is called a wideband system and signals are transmitted over the air in a noise-like manner. Broadband - because it occupies a wide bandwidth. Noise-like signals - because when several subscribers are working on the air at the same frequency at the same time, the signals are superimposed on each other.

CDMA technology has been known for a long time. After World War II, CDMA technology was used for a long time in military communication systems, both in the USSR and in the USA.

1935 - in the USSR, the first work on this topic was published by Doctor of Technical Sciences, Professor, Honored Worker of Science and Technology of the RSFSRD. Ageev.

In the 50s, it was used by the American military communication system, which was used to organize the exchange of voice messages between military aircraft and ground services, as well as to determine the distance to the aircraft.

In 1983, the first Motorola portable cell phone was launched. Weight 1.15 kg, Cost 4 thousand dollars.

In November 1989 in San Diego, the capabilities of a digital cellular communication system based on code division of channels were first demonstrated by the American company "Qualcomm"

In 1995, the first CDMA cellular network (is-95) was launched in Hong Kong, the network was built on Motorola equipment.

Historically, the CDMA standard has been most widespread in North and South America, Southeast Asia:

The evolution of cellular systems using CDMA technology.

CDMA2000 technology development table

multisession network games, etc.

Comparison of CDMA and TDMA (GSM) technologies. TDMA - Time Division Multiple Access -

multiple access system with

time division of the channel.

Access to the base station for several subscribers on the same frequency with time division.

The GSM standard is based on this technology,

From the figure we see that several subscribers communicate with the "base" on one frequency channel, but in turn, at equal, very, very short time intervals, i.e.

several subscribers can talk on the same frequency, but at different times. At any given time, only one conversation, or rather a small part of it, is transmitted on the carrier. In the next time slice, the system will transmit part of another conversation, and so on. On the receiving side, conversations are reassembled from parts into a single whole. The described parts of the conversation are so small that it is almost imperceptible for end users to break up the conversation into such parts.

CDMA - Code Division Multiple Access

With code division multiplexing.

Access to the base station for several subscribers on the same frequency

With code division

When using CDMA technology, all conversations are transmitted on the carrier simultaneously. To understand the organization of the CDMA signal on the air, let's consider an example invented by Motorola marketers.

It is necessary to imagine the "carrier" in the form of some room, at two opposite walls of which there are pairs of people (one person from a pair at each wall), speaking only their own language, and each pair speaks a language different from the languages ​​of the other pairs. At the same time, all pairs speak simultaneously and with the same volume, but do not interfere with each other at all, because for one pair the sounds made by the neighboring pair are nothing more than meaningless noise. Nevertheless, everything that is pronounced by one of the members of the pair is completely understandable against the general background for the second member of the pair, due to the use of a common language that is understandable to both. Returning to real concepts, it should be noted that the room

- this is the carrier, pairs of people at the walls are, respectively, the terminal and the part of the base station serving this terminal, and the unique language is the code that encodes the given talk.

What affects

First of all, on the health of the one who speaks a lot on the phone.

How fast the network works, the speed of data transmission / reception

Differences between the CDMA standard and other digital technologies

High quality of communication Environmentally friendly - safety for human health High speed of data transmission Confidentiality Noise immunity Economical

Higher quality of communication.

In CDMA technology, it is possible to provide high quality speech while reducing the radiated power and noise level. The result is consistently high quality voice and data transmission with minimal average output power.

Environmental friendliness - safety for human health.

A distinctive quality of CDMA technology - lower power consumption of terminals - several times lower value of the output power, which reduces the effect of electromagnetic radiation on the human body by 1.5 - 2 times.

CDMA mobile terminals can maintain a high-quality connection with Base Stations at minimum power. In the worst case, this power reaches 0.2 W (this is the peak value of some older phone models with an unstable connection), usually in units of milliwatts, while in other standards it ranges from 0.6 to 2 W.

In addition, the closer the terminal is to the Base Station, the lower the level of electromagnetic radiation it has.

Due to the low signal intensity, the total level of electromagnetic radiation is much lower than in other standards.

Phones operate by using a power signal at a noise level. This ensures high environmental friendliness and safety for the user.

Oddly enough, this consumer quality is a consequence of the military application of the standard. Following military logic, if it is impossible to find out from the negotiations the final goal of the pilot of the aircraft, there is nothing left but to destroy this aircraft. It is precisely for the difficulty of detecting the aircraft as a signal source, the radiated power of the terminal is significantly reduced.

Higher data transfer rate

The CDMA technology implements original, more optimal algorithms for using the channel resource, which provides wider opportunities for using CDMA terminals in terms of data transmission.

Provides less delay in the transmission of a voice message than other mobile communication systems.

With CDMA, you don't have to use sophisticated echo cancellation tools. The sophisticated error correction method allows you to effectively deal with multipath signal propagation.

This feature provides additional benefits of CDMA in high-rise urban environments.

Confidentiality.

The built-in encryption algorithm and distribution of information over a wide spectrum provides protection against unauthorized access and eavesdropping.

The CDMA standard is the most secure on the cellular market.

Initially, the standard was developed and implemented for communication of pilots with ground services. It was important to "hide" the signal among the noise in order to make it difficult for the enemy to detect such a signal. Even if it was possible to isolate significant signals from the noise, the next problem appeared - the decoding of conversations. Conversations are encrypted using unique codes that require extraordinary processing power to decode.

At the heart of CDMA is a modulation method using a noise-like and wideband signal (sometimes they say "spread" or "spread" spectrum). The useful information is, as it were, "smeared" over the frequency range, which is much wider than with traditional methods of signal modulation (such a signal is often called narrowband). The result is a signal that takes up more

frequency range and has a significantly lower intensity than with narrowband modulation. It is clear that in this case it is possible to receive information only knowing the sequence by which the useful signal was multiplied during transmission - otherwise it will look like noise (hence the name). Therefore, in military applications, this method was used primarily for protection against interference (a broadband signal is very resistant to narrowband interference) and listening.

Immunity.

Noise-resistant - because when a narrow band (200 kHz) noise signal appears in a wide frequency band (1.23 MHz), the signal will be received almost undistorted. The system will recover the lost data due to error-correcting coding.

Interference of industrial origin, for example, cars, is not afraid, since their spectrum is much narrower and is unable to cover the CDMA signal.

The "code" used in CDMA serves not only to identify the conversation, but also serves as a kind of filter that removes distortion and background noise.

In terms of speech quality (naturalness and intelligibility), CDMA parameters are comparable to the quality of wired channels.

Noise immunity is valuable, since not only voice, but also any other information is transmitted over CDMA channels.

If an ordinary user, by and large, is indifferent to whether his voice sounds during a telephone conversation with impeccable purity or with little interference, then errors made during file transfer can violate the integrity of, for example, a corporate database.

Large network capacity.

Fuller use of the frequency resource - CDMA capacity is 10 to 20 times higher than that of analog systems (FDMA), and 3 to 6 times the capacity of other digital systems (TDMA).

CDMA networks make efficient use of the radio frequency resource due to the ability to reuse the same frequencies over the network.

In frequency division systems (both FDMA and TDMA), there is a problem of so-called "reuse" of frequency channels.

In order not to interfere with each other, neighboring base stations (BS) must use different channels. Thus, if a BS has 6 neighbors (the most often considered case, while the zone of each BS can be represented as a hexagon, and everything looks like a honeycomb), then the number of channels that this BS can use is seven times less than the total number of channels in the range allocated for the network. This leads to a decrease in the capacity of the network and the need to increase the density of the BS installation in densely populated areas.

For CDMA, there is no such problem at all. All BSs operate on the same channel. Thus, the frequency resource is used more fully.

One subscriber is "driven" by several base stations.

One of the features of CDMA networks is the ability to "soft" transition from one base station to another (soft handoff). In this case, a situation is possible when one subscriber is "led" by several BSs at once. The subscriber simply will not notice that he was "transferred" by another BS. Thus, communication interruptions during movement are excluded. In addition, by maintaining communication with several base stations (up to 4x) simultaneously, the best signal is selected. Moreover, if none of the channels provides the proper quality, then the signal is built from “bad” components, which together give a good result. If a subscriber, led by three base stations, enters the coverage area of ​​the 4th base station, it acts as a hindrance. The network optimization department is called upon to track the absence of such overlaps. A typical example of the effect of this advantage: in an underpass, where GSM phones can lose connection, a CDMA phone, picking up multiple reflected signals coming from different directions, can confidently keep in touch.

Profitability

The number of base stations required to form quality coverage is significantly lower than that of other standards, which in turn affects operators' capital and operating costs. And the level of costs invariably determines the level of tariffs that the operator can afford in a particular struggle in the communications market.

CHAPTER 3. STRUCTURE OF THE COMPANY INTERTELECOM LLC

General manager heads LLC Intertelecom and carries out general management of its activities in accordance with the provisions of the charter of LLC Intertelecom.

Directly subordinate to the General Director:

- ;

- Deputy General Director for Construction;

- Head of the Department of Technical Operation;

- Head of the Network Planning and Development Department;

- Head of the Information Technology Department;

- Technical directors of regional offices.

The first deputy general director is directly subordinate to:

- Chief Accountant;

- Head of the Department of Economics and Finance;

- Head of Marketing and Sales Department;

- Head of the Customer Service Department;

- Head of HR department;

- Head of the General Department (Head of the Office);

- Director of security;

- Head of the legal department;

- Head of the motor transport department;

- Head of Procurement Department;

- Head of the economic department.

The First Deputy General Director coordinates the administrative and economic activities of the Deputy General Director for Economics and Finance, the Department of Technical Operations, regional offices, the Department of Planning and Network Development.

Head of Marketing and Sales Department the chief managers of the regions are directly subordinate.

Head of Customer Service Department manages the work of subscriber service centers of regional branches and an information support center.

Head of the Department of Technical Operation supervises the directors of the technical directorate of the region.

AGREED

First Deputy General Director

Shulga L.V.

Deputy General Director for Construction

Labor protection department

Network Planning and Development Department

SYMBOLS

Subordination

Coordination

STRUCTURE OF THE MARKETING AND SALES DEPARTMENT

The main tasks of the department:

∙ Formation, development and control of the dealer network functioning:

∙ Development of activities that stimulate sales through the dealership at the national and regional levels;

∙ Control over the dealers' compliance with the terms of the Dealer Agreement, subscriber connection procedures;

∙ Carrying out settlements with dealers.

∙ Negotiating and concluding agreements to expand the network of replenishment points

∙ Interaction with partners in the sale of funds to replenish the account on the transfer of goods and mutual settlements, as well as controversial issues on not accepted from subscribers payments.

LOGISTICS DEPARTMENT

The main tasks of the department:

∙ Sales planning of commercial equipment.

∙ Inventory management.

∙ Setting tasks for sales personnel.

∙ Quality control of sales.

∙ Evaluation of the results of the work of experts in the sale of subscriber equipment.

∙ Coordination of work

Subscriber Equipment Research Department

∙ Studying and predicting the performance of new equipment

∙ Issuance of a technical opinion on subscriber equipment

∙ Writing software that optimizes the work of service centers

∙ Troubleshooting and recommendations for their elimination

Department for the organization of payments and electronic means of payment

∙ interaction with partners providing the opportunity to replenish the account for the company's subscribers. banking and non-banking institutions dealers and distributors selling scratch cards to recharge the account, electronic vouchers.

∙ organization of legal, financial and technical interaction with companies,

providing any possible way to replenish the account by Intertelecom subscribers

STRUCTURE OF THE SUBSCRIBER SERVICE DEPARTMENT

EXPERT CALCULATION DEPARTMENT

The main tasks of the department

∙ timely provision in financial and economic

service of reports on the connections made for all regional offices for the previous month, reports on sold equipment for all regional offices for the previous month.

SUBSCRIBER DEPARTMENT

The main tasks of the department

∙ control over the timeliness of connections and installation of terminals for the privileged category of citizens

∙ timely submission of documentation to district

Department of Labor and Social Protection of the Population for the monthly compensation of the subscription fee for the privileged category of citizens.

∙ monthly, on time, dispatch to legal

persons of tax invoices, detailed printouts for the past period

∙ sending invoices for advance payment, letters of termination of contracts

∙ handling complaints (except for complaints about coverage)

∙ endorsement and accounting of refund applications

∙ work with changes to the model contract for budgetary organizations

SERVICE QUALITY CONTROL department

The main tasks of the department

Mystery Shopper analysis Internal and external audits Conducting knowledge snapshots

control of compliance with standards for the appearance of premises and display of goods control of compliance with service standards analysis of the profitability of the center

HEAD OF SUBSCRIBER SERVICE DEPARTMENT

SERVICE DEPARTMENT

The main tasks of the department

∙ Control over the number of repairs performed, funds received and used spare parts in all service centers.

∙ Ensuring the smooth operation of regional service centers, organizing the timely delivery of spare parts to regional offices.

∙ Providing fast and high-quality service of terminals coming from regional service centers.

∙ Monitoring the implementation of the equipment repair procedure.

OFFICE EQUIPMENT SERVICE DEPARTMENT

The main tasks of the department

∙ Hardware maintenance and uninterrupted

work of computer equipment and printing equipment owned by Intertelecom LLC.

∙ Implementation control by users

rules for the operation of computer and printing equipment;

∙ Control of issuance, movement and write-off of computer

and multiplying equipment within the company, as well as procurement of equipment, consumables, spare parts

and accessories.

RENTAL DEPARTMENT

The main tasks of the department

selection of commercial space, signing contracts, control of rent and utility payments, monitoring of rental prices, work with landlords

Customer service centers

(CALL CENTER)

∙ information support group: operators technical consulting group: engineers group online consultant

∙ corporate clients group

∙ telemarketing group

∙ online consultants

The main tasks of the department

∙ consulting, collecting information, recording

requests from real and potential subscribers of the company, including corporate ones.

∙ informing subscribers about changes in tariffs, conditions, services, etc.

∙ technical consulting of subscribers on setting up equipment (direction of engineers).

∙ customer satisfaction survey

maintenance and services provided by the Company

∙ replies to e-mails of subscribers on the official website of the Company

∙ work with registers of debtors

∙ sales of services by phone

DEPARTMENT OF ECONOMIC SECURITY AND COMBATING NETWORK VIOLATIONS

The main tasks of the department

∙ identification and prevention of types of fraud aimed at unauthorized actions and unauthorized use of the company's resources and services, as a result of which the company LLC

INTERTELECOM suffers loss of income.

∙ Development of algorithms for identifying illiquid connections and abuse in the process of servicing subscribers. Monitoring compliance with the order of connections for compliance with the approved orders and procedures of the company.

∙ Testing of tariff plans, services, special conditions of service, order

connections for compliance with approved orders. twenty

DEPARTMENT OF INFORMATION TECHNOLOGY

HEAD OF IT DEPARTMENT

Tasks of the Department of Information Technologies:

∙ Collection of primary information for further calculations and analysis.

∙ Automated information processing and computational work to generate all kinds of reports at the request of related departments.

∙ Solution of engineering, economic and other problems of production and research nature.

∙ Providing the adjacent departments with the results of calculations.

∙ Study of the information services market for the development of the department and the information structure of the enterprise as a whole.

DEPARTMENT OF ANALYSIS AND INFORMATION PROCESSING

Main tasks:

development and support of software for related departments.

PROGRAMMING DEPARTMENT

Main tasks:

construction and maintenance of the computer network of Intertelecom LLC, communication with branches, operability of the computer park and office equipment, development and support

WEB-applications and website of LLC

Intertelecom.

Service centers Subscriber service centers of the company of subscribers of the company "Intertelecom" "Intertelecom"

CSCs are open in all CSCs are open in all

regions of Ukraine, regions of Ukraine,

where is coverage and where is coverage and

services provided services provided

Serve:

Serve:

Individuals - individuals

Legal entities - legal entities

dealer network dealer network

Dealers - our business Dealers - our business

partners.

partners. Dealer network

The dealer network is represented in each

represented in every region of Ukraine

region of Ukraine

Serve:

Serve:

Corporate clients Corporate clients (SPD and legal entities) (SPD and legal entities)

PROCEDURE FOR CONNECTING INDIVIDUALS AND LEGAL ENTITIES IN THE CENTERS OF SALES AND SERVICE OF SUBSCRIBERS

CONNECTING INDIVIDUALS

To acquaint the Client with the tariffs and rules for the provision of communication services

DOCUMENTS REQUIRED FOR CONNECTING INDIVIDUALS

∙ international passport

conclusion of the Subscription Agreement

∙ a copy of a valid passport of a citizen of Ukraine of one of his parents, in which the Subscriber is entered in the passport

like his child.

If there is no record of children in the parent's passport, the Subscriber submits a copy of his birth certificate.

16 years of age but under 18 who are or have been married

Citizens changing their surname in connection with marriage

(in the passport there is a mark “change within the specified time”)

∙ valid passport of a citizen

Parental permission is not required.

∙ Original marriage certificate

∙ Marriage certificate

∙ passport details to be exchanged

Note:

International passport: the expiration date must be later than the current one.

Correspondence of the photograph in the passport to the bearer's appearance.

If in doubt, the Operator must offer to present another document (driver's license, passport for traveling abroad, military ID, etc.);

The presence of an imprint of the seal of the Ministry of Internal Affairs on the photograph in the passport; Compliance according to the passport of the Subscriber's age;

The presence of the necessary additional photographs (at 25 and 45 years old)

A subscription agreement for this passport can be concluded before the date indicated in accordance with the mark in the passport.

At the same time, it is necessary to enter the data of the passport, which must be exchanged, and the surname must be entered into the billing system.

Required photocopies

the Subscriber's passport (pages with records) where the name, patronymic, surname, series and number of the passport are indicated,

by whom and when it was issued, photograph (at the age of 25 and 45), signature, registration

passport of one of the Subscriber's parents, birth certificate (if the child is not entered in the parent's passport)

Subscriber's passport (pages with records) where the name, patronymic, surname, series and number of the passport are indicated, by whom and when it was issued, signature, registration

Subscriber's passport (pages with records) where the name, patronymic, surname, series and number of the passport are indicated, by whom and when it was issued, photograph (at 25 and 45 years old), signature, registration

passport to be exchanged Marriage certificate (as confirmation of the new surname is provided)

Foreign citizens

Stateless persons

Persons concluding the Subscription Agreement on behalf of the Subscriber

∙ foreign passport

with a note:

O valid registration on the territory of Ukraine with the bodies of the Ministry of Internal Affairs of Ukraine, an entry visa (valid at the moment)

or a mark on crossing the border for citizens of countries from whose territory visa-free entry is allowed)

∙ immigration card, where are indicated:

personal data, host address and visa validity period.

∙ original document replacing passport

(refugee certificate; refugee travel document for traveling abroad

∙ service cards of employees of representative offices

foreign business entities registered in Ukraine

∙ any other document allowing the identification

owner (photo, surname, first name, etc.) with an entry visa or a mark about crossing the border

∙ original power of attorney (notarized or

other form permitted by the current legislation of Ukraine)

∙ original of your passport and copy of the client's passport

Signing copies of documents

Connection is allowed with the provision of both an internal passport of a foreign state and a foreign passport, with the exception of cases of promotional connection.

The presence of a multiple-entry visa (or the presence of a visa for a period of at least six months, valid for this

point in time) or the presence of a mark of registration with the bodies of the Ministry of Internal Affairs of Ukraine.

The immigration card must indicate: personal data, as well as the address of the receiving party (i.e. the address of the place that is the purpose of the visit or the place of temporary residence of the foreign

Connection is allowed except in cases of promotional connection.

The absence of a valid registration in a valid passport of a citizen of Ukraine is not a reason for refusing to conclude a Subscription Agreement.

Passport, Visas or crossing marks

borders (for citizens of countries from whose territory visa-free entry is allowed).

Document replacing passport

In the absence of registration, the last registration address indicated in the passport is recorded as the address of the Subscriber's place of residence.

In the absence and such - the subscriber writes in his own hand the Statement: "Addresses of the place of residence: (indicates the full address)".

Proxy Passport Power of Attorney

The subscriber puts the current date and signature on each page with copies of the documents specified in the table "Required documents for connecting individuals"

(if the signature is different, you must write: "I, full name without abbreviations, I will confirm the signature", put the current date and again my signature (current).

Forbidden:

Use of ready-made certified copies of documents provided by the Subscriber!

Connect the Subscriber if the data of his passport matches the data of the billing system, which reflect:

 the fact of connection of this subscriber on the terms of a promotion with the signing of an additional agreement and the presence of debt for this connection

 a subscriber's statement about the loss or theft of the terminal, registered in a special ("black") list. Statement of loss or theft of the terminal

is registered in a special ("black") list only upon the personal appeal of the terminal owner to the Center of Education and Science upon presentation of a passport. (It is not possible to connect to this particular terminal, which is in the "black" list)

SALES CENTERS ALSO CONNECT LEGAL ENTITIES

3. Bank certificate on opening an account (Issue date no more than 30 days). registry. This document is valid for one month. This document is provided in

Subscriber connection in the "Clients" program:

1. Connect the Subscriber in the "Clients" program with mandatory filling of all fields.

∙ Additional Agreement (s)(if provided by the terms of connection).

An additional Agreement is drawn up and signed for each telephone number if these telephone numbers are on different personal accounts

∙ Certificate of delivery and acceptance of works (for the amount of connection)

∙ Equipment delivery note and warranty card(if equipment is purchased)

Of what the connection fee and what remains about the subscriber:

A package of documents that are being handed over in the archive of the company:

Delivery note for terminals (accounting)

see also

"Instructions for using the application" Clients "as part of the Billing_IT 2.0.5 Billing_IT 2.0.5 Version 2.0 (07.07.2009)"

Information for a new Subscriber of Intertelecom!

Congratulations, you have become a subscriber of Intertelecom LLC! You are the owner of a direct city telephone number.

In addition to the direct city number, you will receive a gift mobile number with the code 094. The last three digits of the 094 number coincide with the last three digits of the city number.

When calling city operators, your direct city number will be determined. When calling mobile operators, the mobile number 094 will be determined. Your friends can choose which number it is more profitable for them to call from their operator.

You have the opportunity to earn by receiving incoming calls to number 094.You can use communication services throughout Ukraine, where the company has coverage,

without additional terminal settings.

When moving from one region to another, the outgoing call rate remains unchanged, as if you are in your city. Incoming calls are also free.

For your number to work, a prerequisite is the timely payment of the subscription fee, depending on the tariff plan you have chosen. The subscription fee for using a direct city number is charged on the 1st day of each month. V

if the funds on the account are not enough to pay the monthly fee, the autoinformer will remind you of this a few days before the start of the new month. If the subscription fee is not paid after 6-10 days, outgoing and incoming calls will be blocked.

To enable the number in the work, you need to replenish the account in a convenient way. When buying promotional equipment, a prerequisite for work is payment of a monthly fee each

month, during the term of the additional agreement.

When you pay a monthly fee, you are credited with bundled minutes that can be used to call local city numbers. The paid subscription fee and the balance of prepaid minutes are not transferred to the next month. The balance of funds on the subscriber's account, in excess of the monthly fee, passes from month to month.

Calls in the national network of Intertelecom LLC between subscribers using regional and regional numbering are free.

Calls within the region, within Ukraine, on the networks of mobile operators and international calls are paid separately - in excess of the monthly fee, depending on the tariff plan you have chosen.

To make outgoing calls, in any direction, the balance of money on your account must be more than UAH 00.00.

There is no connection fee.

Calls are charged per second, starting from the first second of the call.

Having connected on certain conditions, you always have the opportunity to order additional services: caller ID, call forwarding, conference calls, call waiting, voice mail, fax and Internet, Mobile Hit, Vilny Internet, Unlimited access, 3G Access 500.

If necessary, you can use such services as: change of the tariff plan, temporary termination of the contract (in the absence of a valid supplementary agreement), change of owner, change of number, blocking on loss, change of equipment.

For individuals, there is an additional opportunity: to use the self-service system (ACCA) on the company's website https://assa.intertelecom.ua.

You can always get any information you are interested in:

∙ at the company information center by typing* 750 from your number or

∙ number 0-800-50-50-75 / 094 50 50 750 (if you call from another operator's number);

∙ * 800 - for corporate subscribers

∙ on the official website of the company www.intertelecom.ua;

∙ at the Sales and Customer Service Centers of Intertelecom in your city.

∙ By contacting the Online consultant from the main page of the Intertelecom website.

30. Is it possible to use one telephone number on several terminals at the same time?

31. Can I use your services using a GSM phone?

There is no such possibility

No, because the GSM and CDMA standards are based on different technological principles. But the customer service centers have dual-standard telephones.

Additional services

Automatic Caller ID (Caller ID) Call Waiting Conference Call

Call forwarding Complex package of additional services "COMPLIT"

Short Message Service (SMS) Who Calling Service

Service "Back in touch" SIP-number

SIP multichannel International roaming in Transnistria International roaming "Around the world"

100 minutes to mobile networks The whole world with Intertelecom - Russia INTERNET access

Provision of permanent monthly

Reklamny

Administrative services

(paid as a one-time payment upon ordering at the Central Service Center)

Temporary termination of the contract. Extension of temporary suspension.

Reinstatement of the contract (from temporary termination).

Change of ownership. Change of number.

Change of equipment (change of the subscriber form)

Lost blocking Change tariff plan Number deactivation

One-time printout of Internet traffic One-time printout of calls Re-enabling

Standby mode Optional number

Inclusion of the number in the information service of OJSC "Ukrtelecom"

Billing services

(paid upon consumption)

Outgoing calls Internet traffic Sending SMS Receiving / transmitting fax

Confidential call Content services Audiotex

My messages (Mail.Ru, My World, Mail.Ru Agent, Gmail,

One and the same service can be administrative, additional and tariffing, For example: administrative service - upon connection, the service is ordered Fax transmission (activation of 5 UAH) additional service - is paid every month (10 UAH)

billing service - payment for incoming / outgoing connections 0, 20 UAH.

Description of services

Additional services

(paid every month along with the monthly fee)

Automatic Caller ID (Caller ID)

The service will allow you to determine the number of the subscriber calling you and display on the terminal display:

- phone number of the subscriber who called you;

- the name of the caller from your telephone directory (depends on the terminal model).

It is also possible to view on the display of the device (depending on its model) this or that

the number of phone numbers of the last incoming or missed calls.

How to order the "Caller ID" service.

How the "Caller ID" service is charged.

services are paid)

Attention! The service works only if your device supports the automatic number identification function.

Call waiting

The Call waiting service allows you to answer an incoming call while the subscriber is already talking on the phone.

During the call, you will hear a short beep, which means that another call has arrived at your number. In this case, the subscriber who dialed your number will hear the usual long beeps with a sharp break in another key at the end of the beep and the message “Check if the subscriber is rocking”. Thanks to these beeps and messages, you can determine that the person who is being called on the phone is busy on the first line.

You can answer an incoming call without interrupting an ongoing call by pressing the CALL button. Press CALL to switch between conversations.

If you wish to ignore the incoming call, there is no action.

How to order the "Call waiting" service.

You can order this service at ACCA, at the CIP, after being identified, at dealers or at the nearest customer service center by filling out the application form.

This service is included in the work automatically after its order and payment.

How to manage the "Call waiting" service.

Management of the ordered “Call Waiting” service on the terminal is possible as follows: activation - dial * 43 and press CALL

deactivation - dial # 43 and press CALL.

How the Call Waiting service is charged.

Monthly subscription fee:

In most tariff plans it is provided free of charge, (there are tariff plans in which the cost

services are paid)

Call forwarding

This service will allow you not to miss an important call when you are outside the coverage area of ​​LLC

“Intertelecom” when you cannot answer a call or your terminal is disconnected.

A call that arrives at your terminal can be forwarded as to a device in any telephone network, including an international number. The set forwarding will not interfere with making outgoing calls from your device.

There are the following types of call forwarding:

- unconditional (for all incoming calls)

- on no answer from the subscriber

- by number busy

- on no response and on employment at the same time

How to order the Call Forwarding service.

You can order this service at ACCA, at the CIP, after being identified, at dealers or at the nearest customer service center by filling out the application form.

This service is included in the work automatically after its order and payment.

How to manage the Call Forwarding service.

Enabling call forwarding on the terminal is possible as follows:

How the Call Forwarding service is charged.

Monthly subscription fee:

In most tariff plans it is provided free of charge (there are tariff plans in which the cost of the service is paid)

One-time fee for each minute of the forwarded call UAH 0.20. + cost of a call to the destination (depends on the tariff plan).

Conference call

The service allows you to organize a conversation with two subscribers at the same time.

How to order the "Conference Call" service.

You can order this service at ACCA, at the CIP, after being identified, at dealers or at the nearest customer service center by filling out the application form.

This service is included in the work automatically after its order and payment.

How to use the "Conference Call" service.

To create a conference call on the terminal, you must:

1. Establish a connection (incoming or outgoing) with one subscriber

2. Dial the number of another subscriber and press the CALL button

3. After establishing a connection with the second subscriber, press the CALL button again.

How the "Conference Call" service is charged.

Monthly subscription fee:

A one-time fee for each use of the service is calculated as if you made both calls separately - a fee is taken for each of your outgoing calls, depending on its duration and direction.

Complex package of additional services "COMPLIT"

The comprehensive package includes:

Caller ID, Call Waiting, Conference Call, Call Forwarding.

How to order and activate the "COMPLETE" service.

You can order this service at ACCA, at the CIP, after being identified, at dealers or at the nearest customer service center by filling out the application form.

Each of the services included in the package is included in the work automatically after ordering and paying for the service.

How to use and manage the “COMPLIT” service.

Each service included in the package is activated and managed individually, depending on which of the 4 services you want to use. The principle of activation and operation of services from the package is indicated

How the COMPLIT service is charged.

Monthly subscription fee:

In most tariff plans it is provided free of charge (there are tariff plans in which the cost of the service is paid)

Short Message Service (SMS).

Sending SMS.

A subscriber of the Intertelecom company can send SMS-messages (provided that the telephone set supports this function) both within the network and outside it, to subscribers of other operators. Sending SMS messages outside the Intertelecom network is carried out with the participation of a third-party company Global Messaging Center Ukraine (TsGSU). List of operators available for SMS exchange

Order the service "SMS sending"

You can order this service at ACCA, at the CIP, after being identified, at dealers or at the nearest customer service center by filling out the application form.

This service is included in the work automatically after its order and payment.

How to use the "SMS sending" service.

To send messages within the network, the recipient's number must be specified in the long-distance format, both for direct capacity and for mobile:

0 + area code + subscriber number (for example: 0481234567) 094+ subscriber number (for example: 0941234567)

To send a message outside the "Intertelecom" network through the TsGSU, the recipient's number must be specified in the format (for national operators):

0 + operator code + subscriber number (for example 0501234567)

To send a message outside the "Intertelecom" network through the TsGSU, the recipient's number must be specified in the format (for foreign operators):

00 + country code + operator code + subscriber number (for example: 0079152222222 - to send a message to

MTS Russia).

How the "SMS" service is charged.

Tariffication is different, depending on the tariff plan on which the subscriber is served.

Attention! When an SMS is sent outside the Intertelecom network, a message delivery report means that the message has been successfully delivered to the CSGS server, but not to the recipient's terminal. Tariffication of sending SMS occurs in case of successful delivery to the server CGSU.

Receiving "SMS"

A subscriber of the Intertelecom Company can receive SMS-messages:

- from the Company's website www.intertelecom.ua

- from the terminal of the Intertelecom network

- from national and foreign operators connected to the Central State Statistics Service (only to the mobile number 094, when sent to a direct city number, the message will not be delivered)

How to order the service "SMS reception"

The service is available to all subscribers of the Company, there is no need to order it

How the service "SMS reception" is charged

The service of receiving SMS is free in all tariff plans.

A mobile phone is designed for autonomous operation in a cellular network, which is in demand and is dynamically developing. For users, it has become a necessary means of communication. This is a high-tech device that identifies a subscriber using a Sim card. There are many types of phones.

In comparison with each other, they differ in technical characteristics, functionality, design. The cost directly depends on the capabilities of the device, its manufacturer, quality and form factor. There are main types of mobile devices:

• monoblock with keyboard;
• slider;
• cot;
• a mobile phone with a touch screen.

Modern technologies

Progress does not stand still, and now the smartphone has become the most in demand. This is an “intelligent” mobile phone that functions on a par with a personal computer. It has an operating system, and also works with a variety of programs, applications, it has WIFI and GPS modules. This is how it radically differs from a simple telephone.

The phone catalog contains the latest models of devices. The main characteristics of modern smartphones:

• operating system;
• the amount of RAM, built-in memory;
• permission;
• camera;
• monoblock type.

The higher these indicators are for a smartphone, the higher its price will be.

Where can I buy

Online stores offer a wide selection of device models from the most popular, proven global brands: Samsung, Alcatel, Fly, Lenovo, HTC, Nokia, IPhone and others. New, improved models appear. Prices for phones, additional accessories, components, spare parts can be compared using the Aport website. In addition, the site will help evaluate market offers and choose the best seller.

CDMA cellular mobile communication system

In recent years, significant progress in telecommunication technologies has been achieved thanks to the transition to digital forms of communication, which, in turn, are based on the rapid development of microprocessors. One of the striking examples of this is the emergence and rapid implementation of communication technology with digital noise-like signals based on the Code Division Multiple Access (CDMA) method, in the coming years of the new century will eclipse all others, displacing analog NMT, AMPS and others and seriously compete with digital technologies such as GSM.

A remarkable property of digital communication with noise-like signals is the protection of the communication channel from interception, interference and eavesdropping. That is why this technology was originally developed and used for the US military, and only recently the American company Qualcom based on this technology created the IS-95 standard (CDMA one) and transferred it for commercial use. The equipment for this standard is already produced by six companies: Hughes Network Systems, Motorola and Samsung.

General characteristics and principles of operation

The principle of operation of cellular communication systems (CCS) with code division multiplexing can be illustrated by the following example.

Let's say you are sitting in a restaurant. There are two people at each table. One couple speaks to each other in English, another in Russian, the third in German, etc. It turns out that in a restaurant everyone speaks at the same time on the same frequency range (speech from 3 kHz to 20 kHz), while talking with your opponent, you understand only him, but you hear everyone.

Likewise, in the CDMA standard, information transmitted over the air from a base station to a mobile or vice versa gets to all subscribers of the network, but each subscriber understands only the information that is intended for him, i.e. Russian understands only Russian, German understands only German, and the rest of the information is eliminated. The language of communication is currently a code. In CDMA, this is organized by using the encoding of the transmitted data, more precisely, the Walsh function multiplication unit is responsible for this.

Unlike the GSM standard, which uses TDMA (Time Division Multiple Access), i.e. several subscribers can talk on the same frequency as in CDMA, but unlike CDMA, in different time), the IS-95 standard uses the frequency range more economically.

CDMA is called a broadband system and the signals transmitted over the air are noise-like. Broadband - because it occupies a wide bandwidth. Noise-like signals - because when several subscribers are working on the air at the same frequency at the same time, the signals are superimposed on each other (you can imagine noise in a restaurant when everyone is talking at the same time). Interference-resistant - because when an interference signal occurs in a wide frequency band (1.23 MHz), a narrow range (<150кГц), сигнал примется почти неискаженный. За счет помехоустойчивого кодирования потерянные данные система восстановит, см. рис 1, где показан полезный сигнал и помеха (СЗС - селективная помеха).

And in the GSM standard this will not work. Due to the fact that GSM is initially narrowband itself. The bandwidth used is 200 kHz.

Qualcom's CDMA system is designed to operate in the 800 MHz frequency range. The CDMA system is built on the method of direct spreading of the spectrum of frequencies based on the use of 64 types of sequences formed according to the law of Walsh functions. For the transmission of voice messages, a speech-converting device with the CELP algorithm with a conversion rate of 8000 bit / s (9600 bit / s in the channel) was selected. Possible modes of operation at speeds of 4800, 2400, 1200 bit / s.

CDMA channels use rate convolutional coding? (on channels from the base station) and 1/3 (on channels from the mobile station), soft-decision Viterbi decoder, interleaving of transmitted messages. The total bandwidth of the communication channel is 1.25 MHz.

The main characteristics are shown in the table.

The standard uses separate processing of reflected signals arriving with different delays, and their subsequent weight addition, which significantly reduces the negative influence of the multipath effect. With separate processing of beams in each receive channel, 4 correlators operating in parallel are used at the base station, and 3 correlators at the mobile station. The presence of parallel-working correlators allows for a soft "handover" mode when switching from cell to cell.

Soft "handoff" mode occurs by controlling a mobile station with two or more base stations. The transcoder, which is part of the main equipment, evaluates the quality of signal reception from two base stations sequentially frame by frame. The process of choosing the best frame leads to the fact that the resulting signal can be generated in the process of continuous switching and subsequent "gluing" of frames received by different base stations participating in the "handover".

The handshaking protocols in CDMA, as well as in the AMPS standards, are based on the use of logical channels.

In CDMA, channels for transmission from a base station are called Forward, for reception by a base station - Reverse. The channel structure in CDMA in the IS-95 standard is shown in Fig.

Direct channels in CDMA:

1. Pilot Channel - Used by the mobile station for initial synchronization with the network and monitoring base station signals in time, frequency and phase.
2. Synchronization channel - provides identification of the base station, the level of emission of the pilot signal, as well as the phase of the pseudo-random sequence of the base station. After the completion of the indicated synchronization steps, the connection establishment processes begin.
3. Call Channel - Used to call a mobile station. After receiving the call signal, the mobile station transmits an acknowledgment signal to the base station, after which the call establishment and channel assignment information is transmitted to the mobile station via the call channel. The paging channel starts working after the mobile station has received all the system information (carrier frequency, clock frequency, clock delay).
4. Direct access channel - designed to transmit voice messages and data, as well as control information from a base station to a mobile one.

Return channels in CDMA:

1. Access Channel - Allows the mobile station to communicate with the base station when the mobile station is not yet using the traffic channel. The access channel is used to establish calls and responses to messages sent on the call channel, commands and requests to register with the network. Access channels are combined (combined) by call channels.
2. Reverse Traffic Channel - Provides the transmission of voice messages and control information from the mobile station to the base station.

The structure of the transmission channels of the base station is shown in Fig.

Each logical channel is assigned its own Walsh code. There can be 64 logical channels in one physical channel. there are 64 Walsh sequences to which logical channels are assigned, each of which has a length of 64 bits. Of all 64 channels, the first Walsh code (W0) is assigned to the 1st channel, which corresponds to the "Pilot channel", the thirty-second Walsh code (W32) is assigned to the next channel, the next 7 channels are also assigned their own Walsh codes (W1, W2 , W3, W4, W5, W6, W7) to which the call channels correspond, and the remaining 55 channels are intended for data transmission over the "Forward Traffic Channel".

When the sign of the data message bit is changed, the phase of the used Walsh sequence is changed by 180 degrees. Since these sequences are mutually orthogonal, there is no mutual interference between transmission channels of one base station. Interference on the transmission channels of the base station is created only by neighboring base stations that operate in the same radio frequency band and use the same bandwidth, but with a different cyclic shift.

The order of the passage of voice data in a mobile station before sending it on the air.

Let's take a closer look at the structural diagram of the reverse traffic channel. In the forward and backward channels, this pattern is repeated; depending on which channel is currently in use, some blocks of this scheme are excluded.

1. The speech signal is fed to the speech codec.
   At this stage, the speech signal is digitized and compressed using the CELP algorithm ..
2. Then the signal goes to the error-correcting coding unit, which can correct up to 3 errors in the data packet.
3. Then the signal goes to the signal interleaving unit.
   The block is designed to deal with bursts of errors on the air. Bursts of errors - distortion of several bits of information in a row.
   The principle is as follows. The data stream is written to the matrix row by row. As soon as the matrix is ​​filled, we begin to transfer information from it in columns. Consequently, when several bits of information are distorted on the air in a row, when receiving a burst of errors, passing through the inverse matrix, it is converted into single errors.
4. Then the signal goes to the coding unit (from eavesdropping).
   A mask (sequence) with a length of 42 bits is superimposed on the information. This mask is classified. With unauthorized interception of data on the air, it is impossible to decode the signal without knowing the mask. The method of enumerating all possible values ​​is not effective because when generating this mask, iterating over all possible values, you will have to generate 8.7 trillion masks with a length of 42 bits. A hacker, using a personal computer, passing a signal through each mask and converting it into an audio file, then, recognizing it for the presence of speech, will spend a lot of time.
5. Walsh code interleaver.
   The digital data stream is multiplied by a sequence of Walsh-generated bits.
   At this stage of signal coding, the frequency spectrum is spread, i.e. each bit of information is encoded with a 64-bit Walsh sequence. That. the data flow rate in the channel is increased by 64 times. Therefore, in the signal modulation block, the signal manipulation speed increases, hence the broadening of the frequency spectrum.
   The Walsh function is also responsible for filtering out unnecessary information from other subscribers. At the moment of the beginning of the communication session, the subscriber is assigned the frequency at which he will operate and one (out of 64 possible) logical channel, which determines the Walsh function. At the moment of reception, the signal goes in the opposite direction according to the scheme. The received signal is multiplied by the Walsh code sequence
   The correlation integral is calculated from the result of the multiplication.
   If the Z threshold satisfies the limit value, then the signal is ours. The sequence of Walsh functions are orthogonal and have good correlation and autocorrelation properties, so the probability of confusing your signal with someone else's is 0.01%.
6. The block for multiplying the signal by two M-functions (M1 - 15 bits long, M2 - 42 bits long) or they are also called PSP-pseudo-random sequences.
   The block is intended for mixing the signal for the modulation block. Each assigned frequency is assigned a different M-function.
7. Signal modulation block.
   The CDMA standard uses phase modulation PM4, OFM4.

Currently, the equipment of the CDMA standard is the newest and most expensive, but at the same time the most reliable and most protected. The European Community, within the framework of the RACE research program, is developing a CODIT project to create one of the variants of the Universal Mobile Telecommunications System (UMTS) based on the principle of code division multiple channels using wideband direct spread spectrum (DS-CDMA) signals.

The main difference of the CODIT concept will be the efficient and flexible use of the frequency resource. As we explained earlier, wideband CDMA signals are largely unaffected by narrowband interference. Due to this property, the CODIT standard will additionally use guard intervals between carriers for data transmission.