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Subscriber directory mobile communications(part 1)

This article describes some of the concepts used in mobile communications. Without delving into scientific and terminological accuracy, I propose, so to speak, an article based on the FAQ (frequently asked questions) of mobile subscribers. Since I don’t know how to write only in terms and definitions :-), all concepts are accompanied by personal comments using examples, mainly Moscow Operators, although much is applicable for regional ones. All concepts are considered through the prism of how this affects subscribers, special attention is paid to the shortcomings and hidden tricks of Operators, which are aimed at additional deduction of money from subscribers. And the Operators themselves talk about the advantages, sometimes embellishing the reality, as they do in unreliable advertising. Please post your questions, additions and comments in my guest book or on the iXBT forums.

Basic concepts of mobile communication

Mobile communications- this is any radio communication that allows the subscriber to use it without being tied to a specific location: cellular, trunk (or trunking), paging, radiotelephones, radio extenders, walkie-talkies, etc. Cellular connection- a type of mobile communication, organized according to the principle of cells or cells (cells), by placing base stations(BS) (Base Transceiver Station), which cover the local area. The totality of local territories is service area(ZO) Operator. The signal level in a particular location depends on the proximity to the BS, terrain, buildings, industrial interference and other factors. The signal from the BS is transmitted to switch and is processed by it.

Operators publish AO maps, for example, on their websites. Moscow Operators' maps are not very clear - firstly, they publish them without indicating the location of the BS (clumsily referring to secrecy), which reduces their information content, and secondly, sometimes only 3 gradations of signal strength are shown: no signal, zone of possible reception and reliable reception zone. Moreover, instead of logical for clarity color range- white, light, dark, respectively - on some cards it’s like this - white, dark, light. Maybe for an optical illusion? If you look at the map, everything is dark, but in reality, this is just a zone of possible communication :-).

Many regional Operators do not practice open secrets ;-). For example, a model map from the St. Petersburg Operator Fora - and the BS are indicated (they even publish a list of the exact addresses of their installation), and 7 signal gradations.

Cellular standards

Standard cellular communication is a system technical parameters and agreements to ensure the functioning of the cellular communication system. There are 4 cellular communication standards adopted in Russia. Much has already been written about them, for example, but I would like to focus on some points.

NMT-450i(Nordic Mobile Telephone) - old analog standard. In Moscow, this standard is supported by MCC (Moscow Cellular Communications). All Russian NMT Operators form the SoTel network (Russian cell phone). There is an opinion that the quality of NMT communications is poor. This is wrong. Basically, this opinion is imposed by dealers, most of whom connect only to Beeline and MTS because of their more profitable commissions from the Operator. There are much fewer MCC dealers, and MCC is less profitable for dealers. By the way, it would not hurt to pay more attention to working with MCC dealers. For example, this summer dealers more often advocated connecting to MTS, and in the fall to Beeline. By a “strange” coincidence, dealer remuneration from MTS in the summer was much greater than from Beeline, and in the fall it was the other way around :-). Returning to the quality of communication - this is a complex concept: coverage area, sensitivity, ease of dialing, sound quality, connection stability, etc., therefore the quality of communication must be considered according to individual parameters. All these parameters of the NMT-450i are no worse (at least) than those of digital standards. Sometimes NMT sound is criticized, but it is not bad, it is just different: yes, there is interference, noise, “grunting”. Sometimes poor indoor reception in densely built areas or “dirty” airwaves. But the sound itself is more natural, “live” and rich compared to digital standards; there is no digital “gurgling”, “croaking” and failures due to incorrect digitization of sound. If with a poor analog connection you can somehow understand the interlocutor, even through crackling and noise, but with a poor digital connection, with dropped frames and incorrect digitization of sound, sometimes you cannot understand anything. The NMT connection is stable, rarely breaks, and in terms of coverage area, the NMT-450i standard has no equal at all. If you need communication from remote places, then this is what you need, especially with powerful phones, therefore, this standard will live for a long time in the vast expanses of Russia, with the gradual transition of NMT Operators to the GSM-450 standard. By the way, for some reason this standard is officially called GSM-400. The disadvantages of the NMT standard include the “binding” of the phone to the Operator, a small selection of phones, their large size, and inflated prices.

D-AMPS(Digital Advanced Mobile Phone Service) - digital standard. In Moscow it is supported by Beeline-800. Quite popular in Russia, just like its analogue version AMPS.

GSM(Global System for Mobile communications) is a modern digital standard (main in many countries). In this standard, the telephone number and all other information about the subscriber are recorded in SIM-card (Subscriber Identity Module), which is issued to the subscriber upon concluding a contract and can be inserted into any (unlocked) GSM device of the required range, which makes the device itself independent from the Operator. The GSM standard is divided into GSM-450/900/1800/1900 depending on the operating frequency. In Moscow, the GSM standard is supported by MTS (Mobile TeleSystems) and Beeline-GSM. MTS has a main GSM-900 network plus GSM-1800 base stations in problem areas (heavy load) - the center of Moscow, Leningradskoye Shosse and some others. Beeline-GSM has an initial GSM-1800 network, which now covers Moscow and the near Moscow region (in different directions - 20-50 km from the Moscow Ring Road). Then Beeline-GSM began to build the GSM-900/1800 network, which already covered almost the entire Moscow region. In 2001, in the Moscow region, Sonic Duo plans to put into operation the GSM-900/1800 network, as well as the MCC network GSM-450/1800.

The quality of GSM communication is generally good, but, for example, with MTS and Beeline, the quality of GSM sound is somehow flat (to my average consumer’s musical ear :-)), it seems that GSM sound is overly compressed. Low redundancy in GSM audio compression algorithms leads to poor GSM noise immunity - with interference, even small ones, the correct digitization of sound is disrupted and - see above. I don’t know about other Operators, but I wouldn’t like to believe that there is the same one in Moscow true GSM with unsurpassed connection quality:-). And if you take into account the sound quality of some modern GSM phones, or rather stamped crafts in a beautiful wrapper from some manufacturers, then the picture becomes completely sad.

CDMA(Code Division Multiple Access) is a modern digital standard that surpasses GSM in many technical characteristics. In Moscow, the CDMA standard supports Sonet (Personal Communications). In Russia, for some reason, the CDMA standard is certified only as “fixed”, although all subscribers use it, naturally, as a mobile one. Much has already been written about this, as well as about other CDMA misadventures in Russia, for example. Let's hope that CDMA in Russia will overcome the slingshots of officials focused on personal interests and instigated by other Operators. My subjective opinion about the quality of CDMA communication is excellent rich sound, stable connection. Disadvantages: phones are still expensive, limited coverage area. CDMA has (or maybe already had?) another serious drawback - the phone is tied to the Operator (see below for more on this), but it turns out that this is not fatal. Recently, the Chinese company ZTE, under the strict leadership of the CDMA technology leader Qualcomm, released the world's first CDMA phone with a SIM card (!). This little unnoticed revolution may have begun the transition of the CDMA standard from tethered to untethered. If CDMA really does get rid of lock-in, then given the technical advantages of this standard, it will become even more attractive. I would like to believe that communications officials, despite pressure from other Operators, will cancel their order designating this standard as “fixed” in Russia. Moreover, most likely, there is still no escape from CDMA technology - it seems that this technology will be used in the world in third generation communication networks.

"Linked" standards

The (D)AMPS, NMT-450i, CDMA standards are “tied” standards, more precisely standards in which the phone is “tied” to the Operator, i.e. the Operator flashes (programs) the phone itself (and not the SIM card, as in GSM ), which is a big disadvantage for subscribers, causes them a lot of inconvenience, makes the phone itself (and, consequently, the subscriber) completely dependent on the Operator, and the degree of this dependence can be different and, again, is dictated by the Operator. This makes it possible to inflate prices for phones (manufacturers and Operators of DAMPS phones do not abuse this, but NMT-450i and CDMA often do), as well as the possibility of introducing various slingshots.

Here are some typical situations and compare them for “tied” standards and for GSM, the nuances depend on the specific Operator:

The phone is broken

Attached— you take the phone to the service center, hand it in for repairs with all the ensuing “hemorrhoidal” consequences. While you are waiting for your phone to return to normal, the flow of your life is disrupted - your number does not function. And if the phone breaks down somewhere far from a repair civilization, then it’s really bad. If the phone is under warranty, then you may be given another phone with your number for the duration of the repair (by law - three days after the application, and even then not always), but for this you need to go only to certain service centers, for remote areas - “convenience” is obvious. By the way, while the phone is faulty, the subscription fee will still tick, or the expiration date of the card, for example, BI+, will approach (i.e., increase mandatory fee for traffic). You can, of course, block your phone or even write an application to extend the card, but this is an additional hassle and is not always possible.

GSM— move the SIM card from the broken phone to another GSM phone (as a makeshift place, you can buy a used phone of an old model for 20 dollars), and use your number as before. You can, without haste, send a broken phone for repairs or sell the faulty one and buy a new one. And someone will like a makeshift for 20 dollars :-).

You decide to change your phone (but keep your number)

Attached- buy a phone. If it’s a used one, then there may be difficulties - you can run into an active one (not yet disconnected), then they won’t connect it. If it is not active, then it is difficult to fully check its functionality - for example, you cannot call it. Next, you go to the Operator’s office, waste time, write papers and wait for the number to be “transferred” to you (to a used one or to a new one). You can go to the Operator with the old owner of a used phone, but few will agree to waste time on this.

GSM— buy a phone (new or used) and put your SIM card in it.

· You decided to connect with the same phone to another Operator (or temporarily use its services)

Attached— another Operator (with the exception of some CDMA Operators) will not connect your phone while the phone is listed as active with another Operator. The “unlinking” procedure takes time, for some Operators it takes a little time, for others (for example, MCC) it takes quite a long time. There can be no talk of any temporary connection.

GSM— insert a SIM card of another GSM Operator into your phone (unlocked, of course) and use it. For example, in another city it is often much cheaper to connect to a local GSM Operator than to use roaming. The only inconvenience is that the number will be different. But at least the local Operator can be used for local communication.

Have you decided to sell your phone?

Attached- of course, you can simply sell the phone without changing the owner, without further ado. But there is a chance that your former phone(or rather its number) may get stuck in some kind of story, and they will bother you as the legal owner of the phone. Therefore, it is better to cut off the ends - sell the phone officially through a change of owner or by terminating the contract and connecting the phone again. Needless to say, this comes with additional hassle and material costs.

GSM— take out your SIM card and sell the phone. You can easily buy another one in the same way. By the way, there is always a reason to change a GSM phone - new models appear constantly. Many models, modern, with great design on any taste, technically sophisticated, some of them with excellent quality, including sound, tempting you to buy something new. DAMPS and NMT subscribers are deprived of such pleasure - they are forced to choose a phone from a dozen outdated models - the world's leading manufacturers no longer pay much attention to these standards.

So the shortcomings of “tied” standards are obvious. I repeat, I am glad that the release of CDMA phones with a SIM card has begun, so there is a possibility that CDMA will no longer be a “tied” standard and the only thing left to do is to overcome the slingshots of Russian officials :-).

Tariff plans

Tariff plan (TP) - a system of tariffs and a set of services. Tariff plans There are advance and credit. For example, the main TPs of MTS and MSS are advance: there is money in the account - you say, it’s in the red - be healthy, also on BI+. Other Beeline TPs are credit, i.e. payment occurs monthly after conversations. Beeline allows conversations in credit, that is, when the guarantee fee has already been agreed upon and the account has a minus amount, sometimes hundreds of dollars. Therefore, Beeline strictly monitors the purity of the connection - it is almost impossible to connect anonymously (that is, under someone else’s name) (which is sometimes required). The credit system has a number of disadvantages:

• Sometimes unscrupulous dealers connect subscribers using someone else's passport details. Subscribers pay off all the money in the account, get into the red until disconnected, and then the owners of these passports receive bills and have to sort it out. This is the so-called “connection for slaughter”.
• The child “played” with the phone, the subscriber did not calculate the roaming charges while on vacation :-), and the newbie simply did not understand the tariffs and said a lot of money. Of course, you need to be careful, study contracts and tariffs, keep an eye on children, etc., but still...
• Receiving an invoice at the subscriber's address (or at the Beeline office) causes some inconvenience for those subscribers who often move.
• Current control over the expenditure of funds is impossible, Beeline subscribers on credit TPs talk “blindly”, all information about expenses will only be available when the bill arrives. There is not even information about the consumption of “free” minutes. Although this is not a feature of the credit system. After all, it would be possible to do it on credit TPs automated system, similar to ACCA in MTS, which would notify the subscriber about his current expenses.
• The credit system is expensive for the Operator, since it is necessary to spend money on collecting debts, as well as incur losses from unpaid debts and “slaughter”. These costs, by the way, fall on the shoulders of other subscribers. The credit system has not justified itself for MSS - it previously also allowed subscribers to have large debts (even on advance payment plans!), but, apparently, it has become difficult to collect debts, and now MSS does not allow debt from subscribers, and has even begun to include “debt” telephones.
• With the credit system, you have to pay a guarantee fee (deposit), which must be returned when the contract is broken, which is also troublesome - you have to go to the Beeline office, perhaps stand in line, terminate the contract, wait a few days, go again... By the way, for some reason The guarantee fee (deposit) in Beeline is subject to VAT, although according to the Law “On VAT” it should not.

There are also fans of the credit system due to the fact that the subscriber will not be disconnected, as with the advance system, if there is not enough money in the account (usually at the most inopportune moment :-)), but MTS has a useful service for this situation: “Promised payment” "- a subscriber over the phone can take out a loan of up to $10 with subsequent payment within 7 days - very convenient if the account runs out of money, but there is no way to pay yet. And if you carry an MTS Express Payment card with you or you have credit card, there will be no such problems at all.

The so-called card (prepaid) TPs - BI+, MSS-Sekunda, MTS-TAKSAfon - are a type of advance TP. The advantage is payment by cards, a clear account control system, the disadvantage is a limited range of services.

All TPs of Moscow Operators (with the exception of MSS-Conversational) have a subscription fee or other mandatory payments, for example, a minimum fee for traffic, explicit, as on MTS-Local or hidden, as on BI+. Traffic(traffic) is airtime, i.e. the time of using the phone, for a certain period of time (usually a month). Sometimes called traffic amount, spent on communications during this period.

Many Operators have corporate TPs intended for a group of subscribers, payment is made on one invoice. Such TPs are convenient and beneficial for subscribers of one organization or group of relatives. Recent changes in Beeline's corporate TPs have made them the most attractive - the minimum number of handsets on corporate TPs has been reduced from 25 to 10, really not subscription fee on a crooked number, low rates, and with Beeline-800 (DAMPS) all incoming calls are free. True, sometimes Beeline corporate subscribers complain about poor quality service.

Free threshold and per second billing

Free threshold for outgoing/incoming calls in seconds (BP out/in) - non-tariffed interval, i.e. the period of time from start a conversation, which is not charged by the Operator, in other words, the duration of the call for which no fee is charged. A useful thing - if someone called you by mistake, or if you are calling someone, and instead of the subscriber, the caller ID, answering machine (when they are turned on, the time countdown) or the right person If you are not at home, then if you have a power supply you will not have to pay for a failed conversation for a whole minute (on most TPs). In Beeline-800 for credit TPs, tariffs begin from the beginning of the connection, i.e. when the calling tone starts. Monitoring the power supply on NMT and DAMPS phones is difficult, since they show the time not from the beginning of the conversation, but from the moment of connection.

MSS at most TPs has 10out/15in. Beeline's power supply is 9out/9in. Some people think that Beeline on BI+ has a BP at the beginning of every minute, i.e. 1 minute 8 seconds is charged as 1 minute. This is not true, it was only like this on the old BI+GSM TP. MTS has a very small power supply - 5out/5in. It is difficult to fit into this time even with one phrase about “wrong dialing of a number.”

It should be taken into account that all Operators do not charge the time before the power supply, i.e. 5 seconds are already charged for MTS. And if we take into account the possible difference in the measurement of time by the Operator’s equipment and the subscriber’s device, then you can be sure that the MTS subscriber’s conversation was not charged only if the phone display shows 3 seconds (!) or less. I met a more mocking power supply only with NNS - Nizhny Novgorod Cellular Communications (GSM-900) - up to 3 seconds (!). But with NSS, the situation is smoothed out by the fact that its billing is 15 seconds, i.e. if you slightly missed the BP, then they will count 15 seconds, and not a minute, as on MTS. Those who are interested in the power supply on MTS can try to buy a SIM card from old MTS subscribers or subscribers of regional tariff plans, for example, RTK (they no longer connect through them), on which the power supply is 5 out/20 out. BP does not work for forwarded and long-distance calls.

By the way, the power supply problem would really be solved by introducing a real per second payment(i.e. from the first minute) or discrete-second (like NSS). So far, the only Moscow TP with real per-second payment is MSS-Sekunda. For MTS and Beeline-GSM, per-second billing starts from the second minute. On most MSS TPs, on all BI+ TPs, as well as on most other TPs for long-distance and forwarded calls, per minute billing, i.e. 1 minute 01 seconds of conversation will be counted as 2 minutes, i.e. the cost of a minute, by the way, turns out to be almost 2 times more expensive in these cases. By the way, for such TP, minute timers on phones are useless, which will only inform you that the next minute has passed. For such TPs, phones are suitable in which the per-minute signal operates several seconds ahead, and even better are phones with a programmable signal interval, such as, for example, Motorola phones.

Straight and curved numbers

Cell phone numbers can be straight or crooked. Direct- these are ordinary city seven-digit (in Moscow) numbers, curves(or federal) - dial using codes 901, 902, 903 or others, from MGTS phones dial through intercity access via figure eight or through dialing service(SD) is a free service of Operators for calls to crooked numbers without dialing “eight” (it is not always possible, and sometimes “eight” is busy). MTS and Beeline have an automatic SD with the need to additionally dial a mobile phone number in tone mode. Calling a number on a curve is sometimes problematic, since many payphones do not have a tone mode, which is necessary for calls via SD. MSS SD is “live”, like everything analog :-), it is also planned to introduce automatic, through it you can call crooked numbers even from rotary telephones and from old payphones without using beepper(tone generator).

Advantages of a direct number:

• Ease of dialing. There is no need to use the “8”, which is often busy (and sometimes completely blocked) or the dialing service (it is not always possible to use tone dialing).
• You can call from any telephone and payphone.
• Solid, prestigious, easy to remember.

Advantages of a curved number:

• Lower price.
• Caller ID works well.

Calls to crooked telephone numbers of Moscow Operators are free from MGTS telephones (from seven-digit telephones of JSC Electrosvyaz of the Moscow Region are paid). List of telephone series of Moscow Operators. To other crooked numbers, including those using codes 901, 902, calls from MGTS phones are paid, at approximately long-distance rates to the city where the Operator is “registered”.

Caller ID (Automatic Number Identifier)

More precisely in cellular communications it is called CLIP(Calling Line Identification Presentation). If such a service is available, the number of the subscriber calling you is displayed on the display of your mobile phone. In addition to its usual purpose - to know who is calling you, Caller ID is also useful for saving money. For example, depending on the number identified, the subscriber can answer or not answer, but forward the call, or answer within the BP, or call back from a landline phone, etc. Or in order to answer only on-net calls, since incoming mobile calls of the same Operator are free. Or look at the list of missed calls later if it was not possible to answer immediately. Operators guarantee that only mobile phones are identified, although in fact, most landline numbers are also identified on crooked numbers. On direct numbers, only mobile (and digital) phones are detected; Caller ID works well only on some direct series, for example, MTS 231 and 233, Beeline-GSM on series 130 (TP Super-GSM). In general, it is strange that Operators still do not have a full-fledged Caller ID. It is clear that there are some technical problems, including at MGTS, but it is high time to solve them. Since Operators still divide incoming calls into paid and free, then, in my opinion, Operators should provide Caller ID for free so that the subscriber has information about this. Although this is not a lot of money, nevertheless, the cost of Caller ID is up to 50% of the subscription fee for the phone, and this is a fundamental issue. But by and large, there should be civilized TPs with all free incoming calls (like MSS Unlimited-Incoming), since even with Caller ID it is not always possible to understand which Operator’s subscriber is calling you. For example, if the number 8-902-... is identified on the Caller ID of your mobile phone, this does not mean that this is an MTS subscriber. It is possible that this is a subscriber of a cellular non-Moscow Operator, i.e. incoming call from him will be paid (and outgoing calls to him are generally long-distance). You can, of course, look at the list of phone series of Moscow Operators, but you won’t learn it by heart.

AntiAON(CLIR) - allows you to hide your number from the called subscriber. Operators provide an anti-caller ID service, which hides the number only from mobile caller IDs. By the way, MSS telephones are not detected on MGTS caller numbers.

Roaming

Roaming- this is the ability to use a phone outside the Operator’s service area, but in the service area of ​​another Operator with whom there is a roaming agreement. Today, NMT Operators have the most extensive roaming in Russia, but GSM roaming is developing rapidly. IN GSM roaming auto. If there are several roaming Operators in a given location, then depending on the phone model and its settings, either the Operator with the strongest signal strength is selected, or according to a preference list, or manually.

Roaming- very comfortable and useful service, but you shouldn’t use it unless absolutely necessary, at least for now. Today, roaming service is a source of constant complaints from subscribers to Operators. For Beeline-GSM, this is even aggravated by the fact that it is impossible to control your expenses with credit TPs, a surprise bill will arrive after you use roaming, and even with MTS, data from roaming comes with some delay, i.e. a situation is possible in MTS , when your account is already minus, and the phone has not yet been disconnected.

Operators and roaming partners often miscellaneous information about tariffs and services. Sometimes Operators do not bother to notify their roaming partners about changes. Often, Operator directories contain outdated information, sometimes even incorrect reference numbers of the roaming partner, not to mention tariffs, power supply, rounding and other terms of service. Here, for example, is a fragment of a real response to a claim about incorrect deductions when roaming: “Vimpelcom cannot guarantee the accuracy of the information provided by the operator company providing roaming services. This information is constantly changing and depends on the services provided by the “guest network” operator.”.

For some regional Operators, the value of conventional units is underestimated (supposedly cheap :-)), for example, for Kuban-GSM now for some reason “ue” is equal to 21 rubles, which introduces additional confusion in the recalculation of tariffs. When making an incoming call in roaming, the cost of a minute of conversation consists of two components: the fee for long-distance calls in the MTS network and the fee for an incoming call, which is set by the local Operator (sometimes it is not charged). It is also necessary to take into account the peculiarities of tricky tariffing when roaming such services as voicemail and forwarding, it is better to turn off all forwarding settings for the period of roaming.

The subscriber does not always have the opportunity to study all this information, especially for those who are constantly moving. Not all subscribers have the opportunity to constantly monitor the conditions of Operators and choose the optimal one for roaming. The difficulty of “debriefings” is that Operators send to the place of receipt to clarify information communication services, i.e. to the roaming partner. It turns out that the end is in the water, since few subscribers will do this. For example, some of the Operators for some reason do not have a power supply, someone (for example, the independent Kyivstar-GSM) takes money for a failed conversation - for an answering machine message that the subscriber (i.e., you) is unavailable. This is an “excellent” service - while you are unavailable (for example, you are on the subway), then your money is debited, and at roaming rates (!), if they try to call you. Some of the Operators (Russian!) set exorbitant tariffs. For example, calls to Moscow for many Operators reach $2-2.5 per minute (and not necessarily from distant regions), and local calls for some roaming Operators are approximately the same, and, for example, in Khabarovsk and Novosibirsk local calls ( if you use the services of North-West GSM) for MTS subscribers cost about $3.60 per minute! It is better, if possible, to use the services of other MTS roaming partners, respectively DSS (Far Eastern Cellular Systems) and SSS (Siberian Cellular Systems), in this case the call will cost several times cheaper, but another Operator may work better in a particular location. In this case, it is better to install the Operator you need manually.

There are many unsuccessful examples of using roaming, as evidenced by numerous complaints from subscribers about incorrect (or incomprehensible) debiting of money when using roaming. It’s good if there is a meticulous subscriber who pays attention to this discrepancy, but how many other “inaccuracies” are not in favor of the subscriber, of course, that have not yet been noticed by anyone? So it’s better not to use roaming unless absolutely necessary, and if you absolutely cannot do without it, then try to get maximum information about the tariffs and conditions of roaming in the regions where you are going, but this, however, does not guarantee the absence of misunderstandings when using roaming.

SMS

SMS(Short Message Service) - The Short Message Service is a very convenient service for cellular subscribers that allows you to send short (up to 160 characters) text messages to other subscribers. This feature made pagers practically unnecessary, since, having a cell phone, you can use the same service, and for a fee comparable to the fee for paging service. And when you consider that with a cell phone, you can receive messages even if the phone is turned off or unreachable (get it later); transmit messages from it; that the cellular service area is much larger than the paging area (plus roaming); that for some modern telephones are not much larger in size than pagers; Since you can still talk on the phone, it becomes clear why the popularity of pagers has fallen sharply. Using SMS allows mobile subscribers to reduce their costs, since sending messages is much cheaper than minute of conversation, and receiving messages is free (including in roaming). Some TPs charge a small monthly fee for SMS without taking into account the number of messages sent. There are many services for SMS users: various servers for sending messages from the Internet, including from the popular ICQ (program for Internet communication ICQ), you can send a message from a mobile phone to ICQ, to e-mail, you can send messages from a landline phone or payphone - through an operator special service(like a pager) or in tone mode - etc. With the development of e-commerce and other services, the popularity of SMS will increase.

The most developed SMS service is for the GSM standard (MTS and Beeline-GSM in Moscow). In Beeline-800 (DAMPS) you can only receive messages, MCC (NMT-450i) promised to introduce SMS service in September, but still haven't done it. To be able to send messages using a GSM phone, you must register the SMS center phone number specified in the MTS or Beeline-GSM subscriber directory. Unfortunately, competition between these companies sometimes interferes with subscribers - through these SMS centers you can only send messages to subscribers of the same Operator. To send messages from MTS to Beeline or vice versa, you must register the phone number of the SMS center of another Operator that has a roaming agreement with both MTS and Beeline-GSM, for example, the Tatar Operator TAIF-Telkom (+7902390000). By the way, roaming between MTS and Beeline-GSM would greatly help subscribers and overcome the current gaps in the coverage of each subscriber. In the meantime... While they are locking (encoding) phones from each other. Well, thank you for not charging calls to a subscriber of another Operator as international :-).

When choosing an amplification system, it is extremely important to know two parameters: the generation of the mobile network (2G, 3G or 4G) whose quality you want to improve, and the frequency at which it operates.

The fact is that all the main components of amplification systems - antennas, repeaters, modems and routers - are created for specific frequency ranges and very rarely support all existing standards in the world at once. In other words, you can purchase an amplification kit “for 4G Internet,” but if it contains an antenna designed for frequency range, in which your operator does not work, the money will be wasted.

Let's give an example. Most often, 4G Internet is provided at a frequency of 2600 MHz, and most 4G booster kits are designed for this frequency. However, increasingly, domestic operators are beginning to use additional frequencies of 1800 and 800 MHz. If this is the network in your location, then a kit designed for a frequency of 2600 MHz will be useless.

So, to choose a kit, you need to know which technologies you want to amplify and in which frequency ranges they operate. The easiest way to do this is using a smartphone running operating system Android or iOS (iPhone).

Determining the generation of the cellular network

Determining the generation of a cellular network using a smartphone is usually very easy. In most modern operating systems, the data transfer technology is indicated in the status bar next to the level cellular signal. The technology can be specified directly (2G, 3G or 4G) or using one of the abbreviations. The most common designations are:

• 2G, GPRS (G), EDGE (E) - traditional 2G technology, which runs standard GSM voice communication and slow mobile internet;
• 3G, UMTS, HSDPA (H), HSPA+ (H+) - the third generation of cellular communications used for calls and access to broadband mobile Internet;
• 4G, LTE (L) - the fourth generation of cellular communications, currently used by domestic operators only for access to high-speed mobile Internet.

For example, on Xiaomi smartphones with dual SIM cards, the status bar looks like this:

It is easy to determine that the first SIM card of the MTS operator is currently operating in 4G mode, and the second SIM card of Tele2 is in 3G mode.

What frequencies do operators operate on in Russia?

It would seem that once you know what communication standards are available in your location, you can start choosing an amplification kit. However, there is one significant problem: the same communication technology can operate at different frequencies.

Each communication standard (2G, 3G and 4G) contains many substandards. In order for the amplification system to work correctly and amplify exactly the frequency range in which your operator is working, you must first know this frequency range.

The following cellular communication standards are currently available in Russia:

Generation	Frequency ranges	Standard name
		GSM-900, EGSM, GSM-E900
		GSM-1800, DCS-1800

Unfortunately, finding out what frequency your operator operates on is no longer so easy. The developers of the Android and iOS operating systems considered that this information would not be useful to ordinary users, and hid it in a special service menu. Below we will tell you how to call up the hidden menu and find out the frequency used by the operator. But before that - one more important step!

If your smartphone defaults to the network you want to strengthen, no additional action is required. But there are situations when you need to determine the frequency range of another network. For example, you want to find out the 2G frequency, but your smartphone automatically connects to 3G. Another example: you need to strengthen voice communication, and your phone is connected to a 4G network, where only mobile Internet is available. To measure the desired standard, force your smartphone into the appropriate mode.

To do this on Android devices, go to Settings > Other networks > Mobile networks > Network mode and select the required communication standard. Depending on the smartphone model and operating system version, the path to the section Network mode may vary slightly.

Apple smartphones, unfortunately, do not support manual mode switching. Thus, iPhone users can only determine the frequency of the standard in which the smartphone operates automatically.

How to find out the cellular frequency

As we said above, to get information about the frequency at which your smartphone is connected to base station, you need to go to a special service menu. On Android devices it is usually called Service Mode, on Apple smartphones- Field Test. To call up the corresponding screen, just dial a specific number from your phone.

Important! Depending on your device model and operating system version, the instructions in this article may not work. In this case, entering the code will do nothing. Also, on some smartphones the menu may look different, and network information may be in one of the submenus. You may have to search through the menu subsections before you find desired page with information about your mobile connection!

Before testing the frequency, turn off your WiFi connection. If your phone has two SIM cards, it is recommended to remove the unnecessary card and leave only the one that needs to be tested. This way you can avoid unnecessary confusion and get accurate information about the current connection.

How to call the service menu on Android

Depending on Android versions The service menu is opened using one of the following codes:

• *#0011#
• *#*#4636#*#*
• *#*#197328640#*#*

After entering the last character, the hidden menu should open automatically; you do not need to press the call button. On Samsung smartphones You will immediately be taken to a screen with information about the network status. On devices from other manufacturers, you may need to go to the “Phone Information” subsection or another that contains information about mobile connection. Unfortunately, on some Android smartphone models this menu may not be available at all.

On Samsung smartphones, to get information about the network, just dial *#0011#

To obtain network information on Xiaomi smartphones, you need to dial *#*#4636#*#*, go to the “Phone Information” section and scroll down the page. On devices with two SIM cards, there will be two “Phone Information” sections.

As you can see, the hidden menu provides a lot of technical data. We won’t need most of this information, and we’ll tell you what exactly you should pay attention to below.

How to call the service menu on iPhone

On smartphones Apple service The menu is called in a similar way, but using different code. After entering, you must press the call button:

• *3001#12345#*

To get information about your cellular connection, you will need to find the desired submenu item. Depending on your current communication standard, go to:

• for 2G: GSM Cell Environment > GSM Cell Info > Neighboring Cells > 0

• for 3G: UMTS Cell Environment > Neighbor Cells > UMTS Set > 0

• for 4G: Serving Cell Information

Determining the frequency of the 2G network (GSM)

To determine the frequency at which the GSM network operates, a special radio frequency channel number is used - ARFCN. Essentially, this is an identifier that indicates which radio frequency band your smartphone is currently operating in. On the service menu page, the identifier is usually indicated after the designation ARFCN, RX, Rx Ch, Freq, BCCH or other similar abbreviation.

Less often, smartphones in 2G mode immediately display the name of the standard (for example, GSM-900) or the operating frequency. If your smartphone displays the name of the standard ready-made, consider yourself lucky. Otherwise, determine which standard the specified ARFCN belongs to using the table below.

	2G standard	Frequency range
0–124 975–1023

For example, this is what determining the GSM frequency looks like on Samsung smartphones (left) and iPhone (right):

If a smartphone shows several ARFCN values ​​listed in a column, then the active network is usually the first one in the list.

Determining the frequency of the 3G network

The situation is similar with frequency determination in 3G networks. Here the channel identifier is called differently - UARFCN. Unlike 2G networks, two UARFCN values ​​can be specified: one to define the data channel (DL) and another to indicate the data channel (UL). The name of the standard or its special may also be indicated. serial number- the so-called “band” (from the English band).

			3G standard	Frequency range

Thus, in the service menu you can find either the UARFCN value or the serial number of the “band”: for example, Band 1. UARFCN is usually indicated after such abbreviations as RX, CH DL and others. On iPhone, the 3G frequency identifier is called Downlink Frequency or dl_freq.

If a smartphone shows several UARFCN values ​​listed in a column, then the active network is usually the first one in the list.

Let's give an example of defining UARFCN on modern smartphones Xiaomi (left) and Samsung (right). In this case, the frequency of 2100 MHz is used:

Determining the frequency of the 4G network

The situation is similar with 4G networks. The “band” or channel identifier - EARFCN can be indicated here. On an iPhone, the easiest way to determine the 4G frequency is by the “band” specified in paragraph Frequency Band Indicator or freq_band_ind. If a smartphone shows several EARFCN values ​​listed in a column, then the active network is usually the first one in the list.

			4G standard	Frequency range

Note that the last standard cited does not specify different EARFCN values ​​for send and receive. This is not at all accidental. The point is that in LTE standard Band 38 data reception and transmission occurs in the same frequency range, but alternately (TDD technology). A special repeater may be required to amplify this standard.

Below is an example of EARFCN definition on Xiaomi smartphones (left) and latest versions iPhone (right).

On Android devices, you can determine the 4G frequency more easily by using free application CellMapper. CellMapper displays information about the cellular network, including the current band. Unfortunately, it cannot be used to determine the frequency of a 2G or 3G network.

Always determine the frequency at the point where you plan to install external antenna amplification systems. If the operator uses several frequency bands at the same time, the smartphone can use one standard outdoors and another indoors. This is due to the fact that lower frequencies penetrate into rooms better and, as a rule, electronic devices give preference.

For example, if your operator provides 4G Internet simultaneously in the frequency ranges of 800 and 2600 MHz, then indoors the smartphone can select the slower LTE800 standard, and switch to the faster LTE2600 outdoors.

In addition, it should be taken into account that the simultaneous use of two 4G bands opens up the possibility of frequency aggregation for the operator. Aggregation is a function of LTE-Advanced networks, in which subscriber devices use several frequency bands to achieve maximum speed. Today, this technology is just beginning to be implemented by cellular operators, but in the foreseeable future it can significantly improve the performance of the mobile Internet.

If you determine that in your location the telecom operator works in two “bands” simultaneously, it makes sense to think about purchasing a dual-band amplification system.

Generations of mobile telephony

Generation			2.5G		3.5G
Start of development	1970	1980	1985	1990	up to 2000	since 2000
Implementation	1984	1991	1999	2002	2006-2007	2008-2010
Services	analog standard, synchronous data transmission at speeds up to 9.6 kbit/s	digital standard, support for short messages (sms)	large capacity, packet data transmission	even greater capacity, greater speeds	increasing the speed of third generation networks	large capacity, IP-oriented network, multimedia support, speed up to hundreds Mbit/s
Channel width	1,9 kbit/s	14,4 kbit/s	384 kbit/s	2 Mbit/s	3-14 Mbit/s	1 Gbit/s
Standards	AMPS, TACS, NMT	TDMA, CDMA, CDMA One, GSM, PDC, DAMPS	GPRS, EDGE, 1xRTT	WCDMA, CDMA 2000, UMTS	HSDPA	single standard
Net			PSTN,	packet data network	packet data network	Internet

AMPS /D-AMPS /N-AMPS

The AMPS (Advanced Mobile Phone Service) cellular mobile communications system was first introduced in the United States in 1979. The system operates in the 825-890 MHz range and has 666 duplex channels with a bandwidth of 30 kHz per channel. The transmitter power of the base station is 45 W, the automobile mobile station is 12 W, and the portable device is 1 W. The standard uses a number of original technical solutions aimed at ensuring high-quality communications at minimal equipment cost.

Based on this standard, two modifications were subsequently developed: analog N-AMPS (Narrowband Advanced Mobile Phone Service) and digital D-AMPS (Digital Advanced Mobile Phone Service). Both of these options were created primarily to accommodate a larger number of talk channels in a dedicated frequency band. In N-AMPS this is achieved by using narrower channel bandwidths, while in D-AMPS this is achieved by using time division of channels. The AMPS cellular communication system uses base stations with antennas with a radiation pattern width of 120°, which are installed in the corners of the cells. Base stations are connected to switching centers using wire lines through which voice signals and service information are transmitted. The length of the control message transmitted to the subscriber is 463 bits.

The D-AMPS standard has disadvantages: a small coverage area of ​​one base station, increased transmitter power of the base station, poor support among equipment manufacturers, because The standard is already falling out of use. Among the advantages, it is worth noting the relative low cost of organizing a network, fairly high quality and confidentiality of conversations, in the area of ​​reliable reception - automatic switching to analog mode for better voice transmission.

TACS (Total Access Control System), an almost complete analogue of AMPS, is most widely used. In 1985, the first TACS-based network was deployed in England. After that, within a couple of years, TACS networks covered the territories of Spain, Austria, Ireland and Italy. In 1987, the first modification of the standard appeared - ETACS (Extended TACS), which had a slightly larger capacity (640 versus 600 channels). However, despite the improvements, ETACS-based networks have barely spread outside England. The second modification of the standard - JTACS or NTACS (Japan or Narrowband TACS) was intended exclusively for Japan. The differences between NTACS and TACS were, one might say, standard: due to a larger range of allocated frequencies and a smaller communication channel width, the system increased the total number of channels - in fact, NTACS was an analogue of NAMPS. Networks based on TACS turned out to be very tenacious - only in the late 90s did Japan curtail JTACS networks; in the homeland of the standard and in other European countries, this event happened a little earlier.

NMT (Nordic Mobile Telephone) is a first generation public cellular mobile radio communication system. It is one of the oldest cellular communication standards in the world, having been developed in 1978 and introduced into service in 1981. The standard was developed for areas with a large territory and low population density, so it was perfectly suited for Russia.

The NMT standard is analog, hence its main drawback- poor noise immunity; in large cities there is a significant level of interference in the frequency range of about 450 MHz. However, as soon as you move away from the city, the quality of communication improves greatly and sometimes exceeds the quality of wired telephone networks. The main advantage is the large range of the base station. Quite decent communication is observed 70 km from the base station. By comparison, a GSM-900 phone, for example, cannot operate at a distance of more than 35 km from the base station.

The frequency range in which NMT operates: 453-457.5 MHz - for communication from the phone to the base station, 463-467.5 MHz - for communication from the base station to the phone. The channel grid step is 25 KHz (12.5 KHz when using interleaving), the maximum capacity of one base station is 180 (359 when interleaving) subscribers. Transmitter power of subscriber devices is 0.1-6.5 W.

NMT is a federal standard, so you can travel around the country with an NMT phone without fear. About international roaming- here the situation is worse, all over the world NMT networks are slowly being phased out in favor of new, more modern standards.

TDMA (Time Division Multiple Access) - time division multiple access. The TDMA standard is actively used by modern digital mobile communication systems. Unlike frequency division systems, all subscribers of a TDMA system operate in the same frequency range, but each has time restrictions on access. Each subscriber is allocated a time period (frame) during which he is allowed to “broadcast”. After one subscriber completes broadcasting, permission is transferred to another, then to a third, etc. After all subscribers have been served, the process begins again. From the subscriber's point of view, his activity is pulsating. The more subscribers there are, the less often each of them is given the opportunity to transfer their data, and, accordingly, the less data they will be able to transfer. If you limit the needs (capabilities) of a subscriber to a known value, you can estimate the number of users who can actually be served by a system with this method of dividing the environment. Temporary separation is usually imposed on frequency division and broadcasting is carried out in a dedicated frequency band.

Among the three competing cellular standards, TDMA ranks second only to GSM, which dominates Europe. Although this standard often receives little attention in technology discussions, TDMA networks continue to evolve. They are now used in 70 countries around the world and almost completely cover North and South America. The success of TDMA is attributed to the clarity of voice reproduction, which is provided by the new ACELP voice encoder, dual-band and dual-standard phones, increased capacity, global distribution and the transition to the third generation standard UWC-136. According to experts, the increase in the TDMA (IS-136) market reflects the accelerated transition to digital methods and the maturity of this technology. It is important that all three leading digital technologies can become the basis for services wireless communication third generation.

Development of a new pan-European standard for digital cellular communications began in 1985. A special group was created especially for this - Group Special Mobile. The abbreviation GSM gave the name to the new standard. Later, GSM, due to its widespread use, began to stand for Global System for Mobile Communications. To date, the GSM system has developed into a global standard of the second generation, occupying a leading position in the world, both in terms of coverage area and in the number of subscribers.

The GSM standard provides for the operation of transmitters in two frequency ranges: 890-915 MHz (for mobile station transmitters - MS), 935-960 MHz (for base station transmitters - BTS).

The GSM standard uses narrowband time division multiple access (NB TDMA). The TDMA frame structure contains 8 time positions on each of the 124 carriers.

To protect against errors in radio channels during transmission information messages block and convolutional coding with interleaving is used. Improving the efficiency of coding and interleaving at low speeds of movement of mobile stations is achieved by slow switching of operating frequencies (SFH) during a communication session at a rate of 217 hops per second.

To combat interference fading of received signals caused by multipath propagation of radio waves in urban conditions, communication equipment uses equalizers that ensure equalization of pulse signals with a standard deviation of the delay time of up to 16 μs.

The synchronization system is designed to compensate for the absolute signal delay time of up to 233 μs, which corresponds to a maximum communication range or maximum cell radius of 35 km.

The GSM standard chooses Gaussian frequency shift keying (GMSK). Speech processing is carried out within the framework of the adopted system of discontinuous transmission of speech (DTX), which ensures that the transmitter is turned on only when a speech signal is present and the transmitter is turned off during pauses and at the end of a conversation. A speech codec with regular pulse excitation/long-term prediction and linear predicative coding with prediction (RPE/LTR-LTP codec) was selected as a speech converting device. The total speed of speech and signal conversion is 13 kbit/s.

The GSM standard achieves a high degree of security for message transmission; Messages are encrypted using the public key encryption algorithm (RSA).

In general, the communication system operating in the GSM standard is designed for use in various fields. It provides users with a wide range of services and the ability to use a variety of equipment for the transmission of voice and data messages, calling and emergency signals; connect to telephone networks Public Service Network (PSTN), Data Networks (PDN) and Integrated Services Digital Networks (ISDN).

GSM 900 is a digital mobile communication standard using the frequency range 890 - 960 MHz. The GSM 900 standard is widespread in Europe, Asia, Russia and is used by almost all modern European providers, however, it is desirable that, along with GSM 900, the device also supports the GSM 1800 standard, because in this case, if interference occurs on the 900 MHz frequency, the phone will be able to switch to the 1800 MHz frequency.

GSM 1800 is a digital mobile communication standard using the frequency range 1710-1880 MHz. This standard distributed in Europe, Russia, Australia, and the Pacific countries of Asia. When purchasing a mobile phone, you need to find out what standard the local cellular operators use, because... a GSM 1800 telephone will not function in the GSM 900 network, and a GSM 900 telephone will not function in the GSM 1800 network. Almost all modern providers in Europe use the GSM 1800 and GSM 900 standards, so the most popular are dual-band GSM 900/1800 telephones - with When turned on, such a phone itself determines in a split second which frequency the signal is best at and tunes to it.

GSM 1900 is a digital mobile communication standard using a frequency of 1900 MHz. This standard is common in the USA and Canada, so if you want to use your phone in these countries (provided your cellular operator provides roaming services there), your device must support GSM 1900.

PDC (Personal Digital Cellular) is a cellular communication standard used in Japan.The standard is based on a three-slot TDMA solution. In this case, the carrier width is 25 kHz. Despite the fact that PDC networks are located only in Japan, this standard confidently occupies the second position after GSM in the popularity rating among digital standards in terms of the number of subscribers. And this is not surprising: at the beginning of 2000, the number of cellular subscribers in Japan exceeded the number of standard landline telephony subscribers. By the way, it is in Japan that test sections of third generation networks are already operating - despite the rapid pace of development cellular systems communications, the Japanese were more than a year ahead of everyone else.

CDMA (Code Division Multiple Access) - a code division multiple access system - has become perhaps the most promising system to appear on the world market. Decades ago, this technology was used in military communications (USA), and today it is known to everyone as a global digital standard for commercial communications systems. Over the past five years, CDMA technology has been tested, standardized, licensed and launched by most wireless equipment vendors and is already in use around the world. Unlike other methods of subscriber access to the network, where signal energy is concentrated on selected frequencies or time intervals, CDMA signals are distributed in a continuous time-frequency space. In fact, the method manipulates frequency, time, and energy.

CDMA technology makes it possible to ensure high speech quality while simultaneously reducing radiated power and noise levels. The result is consistently high quality voice and data transmission with minimal average output power.

Hundreds of times less output power compared to other currently used standards is a distinctive quality of CDMA technology when considering two important factors:
effects on the human body; operating time without recharging the battery.

CDMA has ten to twenty times the capacity of analog systems and three to six times the capacity of other digital systems. Networks built on its basis effectively use the radio frequency resource, thanks to the ability to reuse the same frequencies in the network.

In terms of voice quality characteristics, CDMA parameters are comparable to the quality of wired channels. Since not only voice, but also any other information is transmitted over CDMA channels, the absence of interference is of particular value. If the average user is, by and large, indifferent to how his voice sounds when telephone conversation with impeccable cleanliness or with little interference, then errors made during file transfer can compromise the integrity of, for example, a corporate database. The “code” used not only serves to identify the conversation of a particular user, but is also a kind of filter that eliminates distortion and background noise. Built-in encoding algorithm provides high degree confidentiality, providing protection from unauthorized access and eavesdropping.

The CDMA system provides lower latency in voice transmission than other mobile communication systems. When using CDMA, you do not have to use sophisticated means to suppress the echo signal. A sophisticated error correction method allows you to effectively combat multipath signal propagation. This property provides additional advantages of CDMA in urban areas with high-rise buildings.

The subscriber does not want to be left without communication when sending a fax when the phone is busy for a long time. CDMA provides an additional service that allows simultaneous voice and fax transmission over the same channel. CDMA technology implements original data packaging algorithms for greater data transmission speed.

WCDMA (Wideband Code Division Multiple Access - broadband CDMA) is the radio interface technology chosen by most Japanese cellular operators and (in January 1988) by the ETSI (European Telecommunications Standards Institute) to provide broadband radio access to support third generation services.

The technology is optimized for providing high-speed multimedia services such as video, Internet access and video conferencing; provides access speeds of up to 2 Mbit/s over short distances and 384 Kbit/s over long distances with full mobility. Such data transfer rates require a wide frequency band, therefore the WCDMA bandwidth is 5 MHz. Technology can be added to existing networks GSM and PDC, which makes the WCDMA standard the most promising in terms of use network resources and global compatibility.

WCDMA (Wideband Code Division Multiple Access) is a technology that uses extended bandwidth and a variation of the DMA principle. It is a third generation mobile radio technology that provides significantly higher data rates than the GSM standard. WCDMA supports voice, image, data and video transmission over mobile networks at speeds up to 2 Mbit/s (local access) or 384 kbit/s (global access). WCDMA is used mainly in Europe during the transition from the GSM standard to the UMTS standard.

The CDMAOne standard exists in variations IS-95a, IS-95b (cellular in American terminology, 800 MHz) and J-STD-008 (PCS, band 1900). The abbreviation IS (interim standard) is used for accounting in the Telecommunications Industry Association (TIA). Typically, CDMAOne networks use IS-95a, which provides signal transmission at 9.6 kbit/s (with encoding) and 14.4 kbit/s (without encoding). The IS-95b version is based on combining several CDMA channels organized in the forward direction (from the base station to the mobile). The speed can increase to 28.8 kbit/s (when combining two channels of 14.4 kbit/s) or up to 115.2 kbit/s (8 channels of 14.4 kbit/s). Actually, in addition to IS-95, CDMAOne networks use a whole set of protocols and standards.

Commercial networks CDMAOne appeared in 1995 and are deservedly popular both in their homeland, America, and in Asia. It is CDMAOne that is meant by the terms “CDMA” and “CDMA-800” (the 800 MHz version, IS-95, is the most widely used). The forward and reverse channels are respectively located in the ranges 869.040-893.970 and 824.040-848.860 MHz. 64 Walsh codes and 1.25 MHz carriers are used.

The CDMA2000 standard is a further development of the 2nd generation CDMAOne standard. Further development CDMAOne was supposed to become IS-95c, and this designation is very often used by manufacturers.

The official update to the standard developed by Qualcomm and approved by the ITU (International Telecommunication Union) is CDMA2000. In Lucent Technologies documents the designation IS-2000 is found. Finally, the International Telecommunication Union (ITU) selected from ten proposed projects five third-generation radio interfaces IMT-2000 (International Mobile Telecommunications System - 2000), including IMT-MC (Multi Carrier), which represents is a modification of the CDMA2000 multi-frequency system, which provides backward compatibility with CDMAOne (IS-95) standard equipment.

Another of the five IMT-2000 standards - IMT-DS (Direct Spread) - is built on the basis of WCDMA projects and is taken as the basis for the European UMTS system.

At the beginning of 2003 Of the 127 million CDMA users, almost 15 million used CDMA2000 technology. During the first seven months of 2002, 11 CDMA2000 networks were launched in Asia and America and the total number of these networks was 18. This is 99% of the 3G market, IMT-MC accounted for 14.8 million subscribers, UMTS - 0.13 million.

However, it is worth noting that the implemented CDMA2000 1X phase is still not full-fledged 3G, because it does not reach the required two megabits. Therefore, it is more often called 2.5G.

Initially, CDMA2000 (IMT-MC) was divided into two phases - 1X and 3X. It is to the first phase that the name IS-95C is applied. And the second was later called 1X-EV (evolution), dividing it into two phases - CDMA2000 1X EV-DO (data only) and CDMA2000 1X EV-DV (data & voice).

And it is the CDMA2000 1X EV-DO standard that is meant by 3G IMT-MC. The 1x-EV-DO standard was adopted by TIA in October 2000 and provides for the following operating scheme: the device simultaneously searches for a 1x and 1xEV network, transmits data using 1xEV, voice - using 1x.

The 1xEV-DV standard fully complies with all 3G requirements. Its practical implementation is planned for 2003-2004.

Now about CDMA-450. It should be noted that the standards of the CDMA2000 family do not require the organization of a separate frequency band and, during their evolutionary development from CDMAOne, can be implemented in all frequency ranges used by cellular mobile communication systems (450, 700, 800, 900, 1700, 1800, 1900, 2100 MHz ).

General Packet Radio Service (GPRS) is a technology standardized by ETSI as part of the Phase 2+ development of the GSM standard and represents the first implementation of packet switching in GSM networks that previously used only circuit switching technology. Instead of transmitting a continuous stream of data over a persistent connection, packet switching uses the network only when there is data to transmit. The use of GPRS technology allows users to send and receive data at speeds of up to 170.2 kbit/s.

The introduction of GPRS technology has brought significant benefits to GSM network operators. For the first time, it became possible to use the Internet Protocol (IP) in GSM networks, as well as connect to a huge number of private and public networks using industry standard data transfer protocols such as TCP/IP and X.25. GPRS is particularly effective when spectrum resources are scarce and allows GSM network operators to offer a wide range of valuable capabilities, increasing their competitiveness.

GPRS is ideal for "pulse" data applications such as email or Internet access. It allows you to establish a "virtually persistent connection" to data sources, so that you receive data as soon as you find it. Such efficiency is achievable in circuit-switched networks. By introducing the GPRS standard, GSM operators have at their disposal networks with third-generation capabilities.

MOTOROLA differs from other manufacturers in that it proclaims the slogan “GPRS everywhere” - in the mass market for horizontal applications (for example, group interactive games), in the business application market for regular mobile vertical access to huge amounts of corporate information (for example, in services delivery).

Enhanced Datarate for GSM Evolution (EDGE) combines a set of new and alternative modulation schemes that can be applied within the GSM radio time domain structure, providing higher data rates or improved spectral characteristics. Phase 1 of EDGE technology (standardized in late 1999) uses GPRS functionality, providing data rates up to 384 kbit/s. Phase 2 (to be developed before the end of 2000) provides real-time services such as audio and multimedia (video).

EDGE is being implemented not only in the GSM environment, but also in the TDMA (IS-136) and iDEN markets in the USA using the same technical standards, to ensure the use of GPRS, and in the future - voice service. Since 384 kbps is the data rate that will be supported by the first phase of 3G networks, EDGE could become an alternative for GSM operators that do not obtain a 3G license, or where the regulator allows it.

1XRTT (One Times Radio Transmission Technology) - 2.5G mobile digital data transmission technology based on CDMA technology. Uses the packet switching transmission principle. The theoretically possible transmission speed is 144 Kbps, but in practice the actual speed is less than 40-60 Kbps. 1XRTT uses licensed radio frequency spectrum and, like others mobile technologies, widespread.

UMTS - Universal Mobile Telecommunications System - is a member of the European family of third generation mobile cellular communication standards. Most of the original goals of UMTS, such as global roaming and personalization of service, were achieved during the development of the GSM standard. The main difference between UMTS is the use of the new 2 GHz frequency range, which allows for a higher quality of service compared to GSM due to increased data transfer rates and channel capacity, as well as the introduction of a packet network architecture that supports voice and data functions.

UMTS provides two main components: a radio network and a bearer network. A radio network consists of mobile equipment and a base station, between which data transmission is switched. The carrier network, in turn, connects base stations to each other, and also creates connections to the ISDN network and the Internet.

With a significantly higher bandwidth (5 MHz) than GSM (200 kHz) and using the CDMA (Code Division Multiple Access) method for transmission, it becomes possible to transmit information of any type (multimedia applications, Internet downloads, video and audio) at high ( 2 Mbit/s) transmission speed.

This makes UMTS up to 200 times faster than the GSM network (9.6 kbit/s). This allows you to transmit 1-2 video sources in real time with full resolution and acceptable quality.

An interesting feature regarding UMTS is not only that UMTS has a very high transmission capacity, but also that it also supports various transmission protocols such as TCP/IP in combination with mobility.

HSDPA (High Speed ​​Downlink Packet Access) is a technology for high-speed packet access over an incoming channel. HSDPA technology is a logical continuation of WCDMA. The standard allows you to increase the data transfer speed in 3G networks by approximately the same times as EDGE technology deployed on top of the GPRS network. In absolute numbers, the peak data transfer speed on the HSDPA network is 8 Mbit/s, while the average is 1-1.5 Mbit/s. For clarity, it’s worth saying that at peak performance on an HSDPA phone you can watch eight digital movies at once.

The purpose of HSDPA is to provide efficient use radio frequency spectrum for services that require high downstream packet data rates, such as Internet access and file downloading. This technology is well adapted to urban and indoor environments.

HSDPA technology is based on adaptive modulation and coding schemes QPSK and 16 QAM; Hybrid Automatic Repeat Request relay protocol; operational determination of the order of packet transmission at the Node B base station using the MAC-high speed protocol. HSDPA is based on a High-Speed ​​Downlink Shared Channel (HS-DSCH), capable of supporting high data rates. The technology can serve different users using time division multiplexing and code division multiplexing, making it ideal for handling intermittent burst traffic in a multi-user environment.

Compared to UMTS, HSDPA can carry three times more data and support twice as many mobile users per one hundred. It is worth noting that currently in field conditions the speed in the 3G downlink (to the user) is about 384 Kbps (theoretically, the speed, according to the 3G specification, should be 2.4 Mbps).

In addition, HSDPA significantly improves the quality of multimedia services provided to the subscriber (due to the high speed, the delay becomes imperceptible, and the volume of transmitted information increases).

Similarly, High Speed ​​Uplink Packet Access (HSUPA) is a mobile communications standard that speeds up data transfer from end-user W-CDMA devices to the base station by using more advanced modulation techniques.

Theoretically, the HSUPA standard is designed for a maximum upstream data rate of up to 5.8 Mbps, thus allowing the use of third-generation applications that require processing huge data streams from a mobile device to a base station, such as video conferencing.

The description of the technology is planned to be introduced as a specification of the 6th version of the 3GPP Release 6 standard; The technology standardization process is nearing completion.

UMA (Unlicensed Mobile Access) is a new solution that allows subscriber devices to operate in GSM/GPRS networks using unlicensed Bluetooth and Wi-Fi channels (802.11). Using UMA technology, operators can offer subscribers roaming and handover services between cellular networks and wireless unlicensed networks of private and public access using dual-mode phones and PDAs.

UMA allows a user within the coverage area of ​​a home or public access point (“hot spot”) to receive high-quality communication services using a single access device and a single telephone number. As a result, we get real convergence of services mobile transmission voice and data with transparent handover (transition of a subscriber from one network to another without loss of connection).

EV-DO is a third generation (3G) mobile network technology standardized by 3GPP2 as part of its development and provides high-speed data transmission of up to 2.4 Mbit/s.

The benefits of EV-DO technology open up a whole series new opportunities for users. In particular, a fast connection to the Internet regardless of location and time of day, the organization of high-speed corporate VPN networks, a wide range of mobile multimedia services, powerful tools for creating mobile “workplaces”. For corporate clients, the use of EV-DO technology can significantly increase employee productivity through universal access to corporate data at any time using secure and simple solutions, improve current business processes and build your business, as well as speed up your response to operational problems and customer questions.

Today, EV-DO technology is used in a variety of areas: in banks and insurance companies, in distribution organizations and entrepreneurs with retail chains, public authorities and users home Internet as an alternative to leased lines or dial-up.

Among the manufacturers of equipment for EV-DO networks are such leading global companies as Lucent Technologies, Huawei Technologies, Nortel Networks, Samsung. Ukrainian operator, operating in the EV-DO standard, is Peoplenet.

CSD (Circuit Switched Data) is a data transmission technology developed for GSM mobile phones. CSD uses a single time slot to transmit data at 9.6 kbps to the Network and Switching Subsystem NSS, where it can be transmitted through the equivalent of a normal modem connection to the telephone network.

Because maximum speed data transmission for a single time slot is 9.6 kbit/s, many operators allocate two or more time slots for CSD calls.

Before the advent of CSD, data transfer in mobile phones was accomplished through the use of a modem, either built into the phone or attached to it. Due to limitations in audio signal quality, such systems had a maximum data transfer rate of 2.4 kbit/s. With the advent of digital data transmission in GSM, CSD provided practical direct access to digital signal, allowing you to achieve higher speeds. At the same time, GSM's use of speech-oriented audio compression effectively means that data transfer rates using a regular modem connected to a telephone will be even lower than traditional analogue systems.

A CSD call works very similar to a regular voice call on GSM networks. A single time interval is allocated between the phone and the base station. A dedicated "sub-time slot" (16 kbps) is established between the base station and the transcoder, and finally another time slot (64 kbps) is allocated for data transmission between the transcoder and the switching center: Mobile Switching Center (MSC).

HSCSD (High Speed ​​Circuit Switched Data - high-speed data transmission over circuit-switched networks) is a multi-channel platform for data transmission in GSM networks. She overcomes limitations wireless networks communication speed, allowing GSM subscribers to transfer data at speeds comparable to and even higher than transmission speeds in wired networks. When using HSCSD technology, the maximum speed can be 57.6 kbit/s. HSCSD is specifically designed to enhance existing GSM infrastructure through software upgrades, making implementation quick and cost-effective.

For end users HSCSD opens up the possibility of a whole range of new wireless communications applications. HSCSD allows you to view WEB pages with more graphic content from a mobile terminal. In addition, users receive high-speed access to LAN and corporate networks.

HSCSD even allows you to organize remote video surveillance in places where laying cable is impractical or impossible. It is also necessary to mention the possibility of organizing video conferences via a wireless interface.

HSPA (High-Speed ​​Packet Access) is a wireless broadband radio technology that uses packet data and is an add-on to mobile networks WCDMA/UMTS.
The technology is based on two previous standards:
- - High-Speed ​​Downlink Packet Access;
- - High-Speed ​​Uplink Packet Access.
IN present moment According to Ericsson's estimates, there are 128 HSPA networks deployed worldwide, and 300 devices supporting this technology are available on the market.

DownLink - communication channel from the base station to the subscriber
UpLink is a communication channel from the subscriber to the operator’s base station.

Standard 4G/ LTE Frequency 2500

This type of communication has been developing relatively recently and mainly in cities.

FDD (Frequency Division Duplex) - DownLink and UpLink operate on different frequency bands.
TDD (Time division duplex) - DownLink and UpLink operate on the same frequency band.

Yota: FDD DownLink 2620-2650 MHz, UpLink 2500-2530 MHz
Megafon: FDD DownLink 2650-2660 MHz, UpLink 2530-2540 MHz
Megafon: TDD 2575-2595 MHz - this frequency band is allocated only in the Moscow region.
MTS: FDD DownLink 2660-2670 MHz, UpLink 2540-2550 MHz
MTS: TDD 2595-2615 MHz - this frequency band is allocated only in the Moscow region.
Beeline: FDD DownLink 2670-2680 MHz, UpLink 2550-2560 MHz
Rostelecom: FDD DownLink 2680-2690 MHz, UpLink 2560-2570 MHz
After Megafon purchased the Yota company, Yota virtually began to operate as Megafon.

Standard 4G/ LTE Frequency 800

The network was launched into commercial operation at the beginning of 2014, mainly outside the city, in rural areas.

UpLink/DownLink (MHz)

Rostelecom: 791-798.5 / 832 - 839.5
MTS: 798.5-806 / 839.5 - 847.5
Megafon: 806-813.5 / 847 - 854.5
Beeline: 813.5 - 821 / 854.5 - 862

Standard 3G/UMTS Frequency 2000

3G/UMTS2000 is the most common cellular communication standard in Europe and is mainly used for data transmission.

UpLink/DownLink (MHz)

Skylink: 1920-1935 / 2110 - 2125 - in the end, most likely these frequencies will go to Rostelecom. The network is not currently in use.
Megafon: 1935-1950 / 2125 - 2140
MTS: 1950-1965 / 2140 - 2155
Beeline:1965 - 1980 / 2155 - 2170

Standard 2G/DCS Frequency 1800

DCS1800 is the same GSM, only in a different frequency range, mainly used in cities. But, for example, there are regions where the TELE2 operator operates only in the 1800 MHz band.

UpLink 1710-1785 MHz and Downlink 1805-1880 MHz

There is no particular point in showing division by operators, because In each region, frequency distribution is individual.

Standard 2G/DCS Frequency 900

GSM900 is the most common communication standard in Russia today and is considered second generation communication.

There are 124 channels in GSM900 MHz. In all regions of the Russian Federation, GSM frequency ranges are distributed between operators individually. And E-GSM exists as an additional frequency range of GSM. It is shifted in frequency from the base one by 10 MHz.

UpLink 890-915 MHz and Downlink 935-960 MHz

UpLink 880-890 MHz and Downlink 925-935 MHz

Standard 3G Frequency 900

Due to the lack of channels on the 2000 frequency, frequencies of 900 MHz were allocated for 3G. Actively used in the region.

Standard CDMA Frequency 450

CDMA450 - in the central part of Russia, this standard is used only by the SkyLink operator.

UpLink 453 - 457.5 MHz and DownLink 463 - 467.5 MHz.

The gradual development of cellular communications in the world is called Generations - there are 4 generations of cellular communications. At the moment, there are 4 generations in the world: 1G, 2G, 3G, 4G.

Each generation includes communication standards used by the Buyer. In Russia, all generations of communications were put into commercial operation, and most widespread received communication standards of the second generation GSM (GI-ES-EM), and third generation UMTS (U-EM-TE-ES). Surely you have already guessed that the popularization is caused by the numerous advantages of the mentioned standards.

1. Cellular standards.

The cellular communication standard is a set of rules according to which the operator offers communication services to the Buyer. A communication standard is the rules by which a network operates. Rules that allow you to separate one call from another and communicate comfortably. At a time when telephone communication was just in its infancy, the standard of communication was the telephone operator switching plugs according to the client’s requests, you probably remember this from old films. Modern communication standards, along with the ability to make calls, allow you to send text and multimedia messages and even use the World Wide Web!

1st generation is 1G(1 JI) the first connection in the world. In networks of this generation, only calls were possible. There were no services such as SMS, Internet, and there were no SIM cards either . In the first generation standards, to connect the phone with the base station, it is used analog signal transmission system. As a consequence, such a system has poor protection against interference and high energy consumption, so communications are no longer used due to its critical shortcomings. After all, the most important thing is the quality of communication, right?

To generation 2G refers to the GSM (GSM) standard - it makes it possible to use SIM cards, send messages and use the Internet.

In second generation standards, to connect the phone with the base station, it is used digital signal transmission system. Compared to analogue systems (1G), they provide subscribers with a larger range of services, are protected from noise and interference, and are much better protected from eavesdropping. The second generation digital standards (2G), which have become widespread in the Russian Federation, include the GSM standard (GI-ES -EM), - from English. Global System for Mobile Communication – “Global Mobile Communications System”.

Due to the different terrain and population density, it became necessary to introduce several GSM frequency bands. Currently, four GSM frequency bands are used in the world: GSM 850, GSM 900, GSM 1800, GSM 1900.

GSM900/1800 are used in Russia, Europe, Asia, Africa and Australia.

GSM850/1900 are used in the Americas.

Changing the radio frequency affects the cell coverage area and the maximum number of subscribers in it. As the frequency increases, the size of the cell decreases, but the penetrating ability of the signal increases, and this helps to improve the level of signal reception (for example, in concrete-metal structures), and the number of communication channels also increases. As a result, an increase in frequency leads to servicing a larger number of subscribers over a smaller coverage area, so high-frequency standards 1800 and 1900 are used in cities, and low-frequency standards (900 and 850), for the sake of economy, are used in rural areas, since they have a much larger coverage area .

And all the telephones that we sell in stores are divided into dual-band (900/1800), tri-band (900/1800/1900) and quad-band (850/900/1800/1900).

If a client expresses the need to travel to countries in South and North America, it is important to make sure that the telephone you are selling him supports 850/1900 frequencies.

The GSM standard uses a special subscriber authentication module – a SIM card – to protect against unauthorized connections. (SIM card).

SIM (Subscriber Identification Module) is an individual subscriber identification module. This card, whose built-in chip stores special information about a specific subscriber, is issued to him when he connects a phone and can be used with any model of GSM mobile device.

Thus, the subscriber gets the opportunity to painlessly change devices without moving the card from one to another. To prevent someone else from using the SIM card, it contains a special identification number (PIN code) that is requested each time the device is turned on. The PIN code request can be disabled through the device menu. If you enter the PIN code incorrectly three times in a row, the SIM card will be temporarily blocked. Unlocking is carried out using an additional unlock code (PUK). Entering the PUK code incorrectly 10 times in a row will result in the card being permanently blocked. Such a card can only be restored by personally contacting the operator’s office. The SIM card also allows you to save subscriber numbers (up to 250 entries), as well as SMS messages (up to 30 pieces) in memory.

The speed of Internet access in the GSM standard depends on the GPRS (DZHIPIERES) or EDGE (EDGE) services, and the difference between them is only in speed.

GPRS (GIPIERES) – packet data transfer will allow the Buyer to exchange data with other devices on the GSM network and with the Internet. In this case, the Buyer, when using the service, pays only for the information received/transmitted. Maximum theoretical speed V = 171.2 kbit/s.

F The actual data transfer rate is significantly lower than the theoretical one. When GSM networks are congested with voice traffic, the average speed received by a GPRS subscriber, as a rule, does not exceed 20-30 kbit/s.

EDGE (EDZH) - is an “improved” version of GPRS with similar characteristics. Greater EDGE speed is achieved by introducing an improved system for processing transmitted data. The buyer, when using the service, pays only for the information received/transmitted. Maximum theoretical speed V = 384 kbps.

F The actual data transfer speed using this technology depends on the network load and its quality at the subscriber’s location, averaging 100–130 Kbps.

Third generation 3G(3 GI) is represented in Russia by two communication standards -UMTS(U-EM-TE-ES) andIMT- M.C.450 (I-M-TI-MC-SI 450), which allow operators to provide a wide range of services.

Of course, third generation communication standards have a lot of advantages over second generation standards:

high sound quality and low background noise;

increased system capacity (number of subscribers) 3-5 times greater than in GSM;

provides complete protection against unauthorized connection;

reducing the impact on the human body, which means you can carry the phone in your pocket, on your neck and put it under your pillow before going to bed.

Third generation communication standards provide not only the provision of traditional mobile communication services, but also fundamentally new services based on high-speed data transmission:

video telephony or video call – allows you to see the interlocutor during a conversation;

mobile television – allows you to watch TV shows on your mobile phone screen;

video surveillance of remote objects from a cell phone display;

high speed wireless Internet access.

Standards for BuyersUMTSAndIMT- M.C.450 is an excellent connection and high-speed Internet access.

On April 20, 2007, the Ministry of Information and Communications of Russia officially awarded the representatives of the Big Three - Beeline, MTS, Megafon - licenses for the development of third generation networks - UMTS. The number of Russian cities in which 3G UMTS networks are deployed is growing every day. The UMTS standard operates at a frequency of 2100 MHz, which significantly increases the quality of communication.

The main data transfer protocol used in 3G networks:

HSDPA (HSDPA) - high-speed packet data transfer from the base station to the mobile phone, the maximum data transfer speed is 14.4 Mbit/s.

Feature: the cell radius for full provision of services is 1-1.5 km.

The IMT-MC-450 standard network was launched on October 1, 2000 in South Korea. Since June 2003, the IMT-MC-450 standard has been used in Russia by one operator - SkyLink. The IMT-MC 450 standard operates at a frequency of 450 MHz, which significantly increases the communication range.

Data transmission technologies used in the IMT-MC450 standard:

EV-DO (Evolution Data Only, from English. Development of data) - up to 3.1 Mbit/s.

Advantages of the standard:

even higher sound quality and low background noise;

The network capacity is higher than in the UMTS standard, this makes it possible to get through and congratulate everyone on the New Year;

reducing the impact on the human body, the emitted power is about 10 mW (0.1 W);

D To use cellular communicationsIMT- M.C. 450 (Skylink), the client needs to buy a cell phone that supports this standard and a RUIM (Removable User Identity Module) card, which is indistinguishable from a SIM card.

The specifics mentioned above cause differences in operators, services and devices. Phones of the IMT-MC-450 standard in Russia are currently presented by companies less familiar to subscribers of the second generation network - these are Huundai-Curitel, Synertek, Pantech-Curitel, Ubiquam, Huawei, AnyData and others.

The UMTS standard, unlikeIMT- M.C.450 gives Buyers the opportunity to make video calls and watch TV programs. Thanks to the camera located on the front panel, UMTS phones support video calls, which allow you not only to hear, but also to see your interlocutor. Back in 2007, the first video call was made in Russia on a third-generation cellular network. At the moment, the video call service is already available in most regions where 3G UMTS networks are deployed. And thanks to the high data transfer speed via the HSDPA protocol, UMTS phones can also be used as a pocket TV that is always with you.

P watching TV shows and videos (for example, withYouTube) is possible both through specialized programs that we can install for the Buyer, and through the program–browser built into most phones.

4th generation (4G) is a high speed Internet access, more than 3G, but there is no ability to make calls. The standards of the fourth generation, as well as the second and third, refer to digital standards. From a technical point of view, the main difference between fourth-generation networks and the previous, third, is that 4G technology is entirely based on packet data protocols, while 3G combines the transmission of voice traffic and “packets”. The fourth generation of mobile communications is characterized by high data transfer speeds and improved quality of voice communications. The fourth generation includes technologies that allow data transmission at speeds exceeding 100 Mbit/s, which is comparable to the speed achievable by fiber optic technologies.

IN important to know, networks 4GThey only provide internet access. Call in 4Gis not possible (you can only call via Internet services –Skype, Mail. ru Agentetc.). Also noSIM-cards in 4GNo. To use 4G

it is enough to buy a special device - 4Gmodem and connect it to the computer.

One of the data transmission standards implemented in Russia by 4G operators is WIMAX (VIMAX).

In 2008, Scartel launched the Mobile WiMAX network under the Yota brand in Moscow and St. Petersburg. Yota is the first 4G network in Russia. The WiMAX standard operates at a frequency of 2500-2700 MHz, which significantly increases the quality of communication.

WiMAX (Worldwide Interoperability for Microwave Access) is a telecommunications technology designed to provide universal wireless communications over long distances for a wide range of devices, from workstations and laptop computers to mobile phones.

Mobile WiMAX is the next generation of wireless broadband (4G). In the Mobile WiMAX network, users can surf the Internet with the comfort of cellular communications and the quality of a leased line. Like wired broadband access, which is now the most common type of connection, Mobile WiMAX gives the user high speed Internet access - up to 10 Mbit/s, and a maximum theoretical speed of up to 100 Mbit/s! This allows you to quickly download large files (for example, movies), watch videos or TV shows, and participate in online games in mobile mode.

The following types of user devices are already presented on the market: USB modems, express cards and multi-user mobile WiMAX Wi-Fi (WiMax Wi-Fi) center, which, in addition to WiMAX, serves as a Wi-Fi access point, and also makes it possible to connect devices wired to the Internet of two regular telephone or fax machines.

Advantages:

The 4G standard is based on the Internet Protocol, which will provide simple and very quick access to the Internet;

high capacity, throughput networks;

large range of WiMAX base station up to 10 km;

high data transfer rates, allowing you to receive not only high quality sound, but also video.

In Russia, access to the WiMax network is provided by two companies Yota and Comstar.