Phones with two standards cdma and gsm. CDMA and GSM phones. Why CDMA is better

What's the difference between GSMAndCDMA?

As a rule, people do not think much about the difference in communication standards when choosing a mobile operator. But there are differences between them.

The first communication standards belonged to generation 1 G , which are wireless analogues of conventional telephone communications. But there were a number of disadvantages: the power of the transmitters was so high that it could have a bad effect on human health, the small capacity of the base stations, poor protection against interference, etc.

1 G was replaced by 2 G.

The first digital standard was GSM with improved protection against interference, good quality of speech transmission due to the voice codec, protection against interception. It began to appear in 1991, gradually replacing all other standards. It was developed by the European Institute for Communication Standardization ( ETSI).

In 1993, Qualcomm technology CDMA developed a new standard IS-95 (cdmaOne), which appeared on the market in 1995.

Below we will try to figure out what the main differences between CDMA and GSM , and what are their advantages.

DifferencesCDMAAndGSM

The most important difference between these standards is the ability to work with frequency resources.

GSM uses channels separated by time and frequency, allocating for each subscriber a small frequency band over which the phone communicates with the base station. But at the same time, data exchange sessions are recorded in time. The signal is interrupted, but because... high frequency is used, the subscriber does not notice it. But in real life, this can be noticed by the beeping sound in the speakers, which appears if there is a phone nearby that is receiving a call or a message or notification has arrived.

CDMA uses code division. Any subscriber who has a connection to the base station can use the entire available frequency resource, which is common to everyone, and the base station communicates with everyone. Each subscriber is assigned a specific code that distinguishes him from the general radio airwaves.

Below is an example for a general understanding of how communication standards work.

Let’s say there is a group of subscribers in the room, divided into pairs. The first part speaks one language at a time, for example for 30 seconds - scheme of work GSM.

And the second part speaks simultaneously in different languages ​​- scheme of work CDMA.

Advantages of CDMA and GSM

The difference lies in the operating principles. Frequency band CDMA is wider than GSM - which result in certain advantages:

The quality of voice transmission is better, because the wider the frequency band, the more resistant it is to interference

Safety, because if you intercept the signal CDMA , then it will look like noise, from which it is difficult to identify a specific subscriber.

Less energy consumption of the communication device, because signal strength CDMA is less than GSM and depends on the distance to the base station. It is more difficult to isolate such a signal, because it has less power.

Advantage of CDMA is a large capacity of base stations, range, simplicity in network setup, resistance to overloads. CDMA - Operators are able to cover a larger area with less equipment that is easier to set up.

So why if CDMA better, the most common standard is GSM ? At the time of creation CDMA GSM has already found its niche in the market with a ready-made selection of equipment for operators and consumers. Here's a more perfect one CDMA required considerable computing power, the creation of new solutions for new technology, and communication devices were more expensive than for GSM , plus they didn’t have compatibility yet.

And of course, ease of use played a significant role.

On GSM network the user could save the information to SIM -card, and when changing the phone you can simply rearrange it SIM-ku.

On a CDMA network the data was stitched into the phone itself, which did not have a slot for SIM -map. Therefore, when changing the phone, all the data had to be re-flashed.

For the CDMA standard, an analogue of SIM -cards appeared in 2002 - R-UIM . The emergence of dual-standard telephones also began. Therefore, gradually the problem with the choice was solved. American operators played a major role in giving impetus to the development of the standard. In Ukraine CDMA occupies a noticeably smaller share, the choice of phones is smaller, but some of the equipment is imported by operators, and subscribers themselves can buy a phone on international sites.

Considering the pros and cons, it turns out that from a consumer point of view, the standards look similar, the final choice comes down to operator coverage.

Evolution of communication

The above data was made on the basis of ordinary telephone communication, but in the modern world, simply talking has long become one of the operator’s services.

Let us now consider the quality of communication from the Internet access side.

Originally GSM gave the highest possible data transfer rate - up to 9.6 kbit/s. GPRS and EDGE technologies related to generation 2 G , developed this speed to 474 kbit/s. In generation 3 G technology is used to transmit data WCDMA , which is a derivative of CDMA.

CDMA initially had a high safety margin and provided the highest possible transmission speed - up to 153 kbit/s. AT 3 G networks used EV-DO technology for data transmission. Depending on the standard of the generation implemented - REV - the maximum transfer speed increased from 2.4/153 Mbit/s (Rev.0, upload/download) to 73.5/27 Mbit/s (Rev.B).

The figures given for each communication standard are approximate, because... actual access speed may be much lower.

Theoretically, further development is possible 3 G networks, increasing data transfer speeds, but in practice this looks dubious. So far, the available speed is enough to meet user requests.

High-speed 3G Internet from GSM operators is already in full swing across Ukraine. But despite the relatively rapid development of the capital and some regional centers, progress in small settlements is not yet visible. The same cannot be said about 3G from Intertelecom. Therefore, today operator’s mobile Wi-Fi modems are quite popular, but few people know that you can make voice calls on the GSM network and use 3G Internet on the Intertelecom network on one smartphone. We decided to figure out how convenient and profitable it is.

Today in Ukraine you can find not many smartphones that allow you to simultaneously work with GSM and CDMA cards. For testing purposes, we were able to easily obtain two models: HUAWEI Ascend P6-C00 and Lenovo A330e.

HUAWEI Ascend P6-C00 is a mid-level smartphone. At the same time, it has a very good IPS screen, a nice design in a thin metal body and normal performance. We won’t talk much about it, because in our editorial office we had a GSM version of the device, which is not much different from the P6-C00 model. You can read the review.

Lenovo A330e is a new smartphone that recently appeared in the Intertelecom line, but what makes it stand out is its good battery life and low price. It uses a 2-core Qualcomm Snapdragon 200 MSM8610 chip with a clock frequency of 1.2 GHz as a processor, the amount of RAM is only 512 MB, and the built-in 4 GB is expandable via microSD memory cards.

As you can see, choosing a smartphone with CDMA + GSM support is quite a difficult task. If you are not a demanding user, then you can limit yourself to the devices that we described above. But on the Intertelecom website in the “Smartphones - Exhibition Equipment” section you can find more interesting models that support operation in the CDMA network, although they are not supplied en masse to Ukraine.

For example, Samsung Galaxy Note 4 N9109W, which also supports GSM and CDMA networks, but according to the EV-DO Rev.B standard. Or Samsung Galaxy A3009 A3, which is a more affordable option, but does not support EV-DO Rev.B.

Coating

Let's immediately figure out the answer to this question. If you are not in the regional center, or even in the immediate vicinity of it, then 3G Internet from GSM operators may not appear there soon. Intertelecom is also not entirely ideal, but at least it exists in most of Ukraine.

At this link you can see a detailed map for each region.

Speed

Data transmission in the CDMA network is carried out according to two standards: EV-DO Rev.A and EV-DO Rev.B. The first has greater coverage, but is limited to a maximum data transfer rate of 3.1 Mbit/s. The second provides data transfer speeds of up to 14.7 Mbit/s, but not such wide coverage. To watch YouTube videos in 720p quality, the speed of the EV-DO Rev.A is sufficient. In addition, you can count on comfortable surfing the Internet and fast loading of social networks. This has been tested on the basis of HUAWEI Ascend P6-C00 and Lenovo A330e, which can only operate according to the EV-DO Rev.A standard.

Real speed measurements do not show the best results, but this is a good solution for those who live in small towns or often travel around the country.

Rates

If you use a GSM SIM card only for calls, and a RUIM CDMA card for the Internet, you can save a lot of money. If you have a smartphone with CDMA support, but you only want to use the Internet, then you should look at tariffs without voice services. They are much cheaper.

The “Super 3G Tablet 40” tariff plan includes 3000 MB/month for speeds up to 14.7 Mbit/s; if you exceed this limit, the speed is cut to 128 Kbit/s, and the amount of traffic is unlimited. The cost of this tariff is 20 UAH/month.

The “Super 3G tablet 70” tariff plan includes 5000 MB/month. The following conditions are the same, but the cost is 50 UAH/month.

For those who want to use the Internet only on selected days, tariffs with “Unlimited Mega Day” or “Vilniy Day+” with 1000 MB/day and 1500 MB/day, respectively, are suitable. The cost of these tariffs is 5 and 7 UAH for each day of use.

If your smartphone requires not only Intertelecom mobile Internet, but also voice communication, for example, with a landline number, you can connect to the Smartphone 30+ and Smartphone 50+ tariffs. The first includes 500 MB of traffic, unlimited calls on the Intertelecom network, as well as 40 minutes to the networks of other operators and landline numbers in Ukraine for a monthly fee of 30 UAH/month. In the second, for 50 UAH/month, 2 GB of traffic, unlimited calls to the Intertelecom network and 150 minutes to other networks and landline numbers are available.

conclusions

The second card with 3G from Intertelecom is a fully functional and already proven effective option for mobile Internet, including for residents of small towns or rural areas. And the ability to use two standards in one device itself is quite convenient, but it is not suitable for everyone due to the small selection of equipment in our country. Although it is quite possible to find a flagship GSM/CDMA smartphone, as we see with the example of the Galaxy Note 4 N9109W, its price will be much higher than that of the same HUAWEI Ascend P6-C00 and Lenovo A330e.

In this review we will talk about the CDMA communication standard - we will discuss the characteristics and principle of operation, and provide a full detailed description. Let's look at the differences from other standards, the spread of technology in Russia, and tell you about special smartphones.

Description and characteristics

Let's start the article by defining what it is, CDMA in a smartphone.
CDMA is (from the English Code Division Multiple Access) a second generation communication standard, which is an analogue of GSM.

Please note that these are not interchangeable technologies, but two methods of communication that compete with each other. What is the difference between CDMA and GSM? We'll talk in detail below.

The connection of two subscribers within the framework of this technology occurs through the allocation of a frequency spectrum, identification of connections is carried out using special codes.

For now, let's look at the advantages of the technology:

• Excellent information security;
• Good voice sound when calling, no interference;
• Minimizing communication failures;
• High data transfer speed;
• High capacity of the cellular network;
• Economical battery consumption;
• Reducing the radiation level of a mobile device.

The standard was adopted in 1992, although developments took place much earlier, and has become widespread in many countries around the world. Until now, CDMA phones are actively used in various countries - in African countries, China and others.

CDMA-450 or CDMA 2000 appeared in 2000 - the standard operates at a latitude of 450 MHz and was actively spreading in Russia, mainly the CDMA communication standard was present in Moscow.

At the moment, in 2018, all CDMA operators in Russia are closed; not a single telecommunications company provides such services. In our country, a more familiar format is used - GSM.

Differences from GSM

Let us highlight the differences between the technology described above and GSM. Despite the fact that both standards belong to the same generation, they have a slight difference in operating principles:

• Ability to interact with frequency resources. GSM uses time and frequency separated channels, while the second technology is based on code division channels;
• The SDMA frequency band is wider than that of its competitor, which improves the quality of speech transmission and reduces the level of interference;
• Lower energy consumption, since the signal power is significantly reduced and depends on the distance to the base station;
• SDMA has a large station capacity, wide range and easy network setup.

What is the difference between WCDMA and CDMA - WCDMA technology is a derivative of SDMA and belongs to the third generation of mobile communications (3G). At the moment, these technologies cannot be used simultaneously and are a transitional stage to the latest standard - LTE.

Smartphones

In this part of the section, we will discuss dual-standard smartphones. At the moment, both second-generation standards described above are widespread throughout the world and cannot be used simultaneously - but there is one exception.

These are special devices designed for use in two networks simultaneously - the capabilities are expanded by installing special software. Smartphones are equipped with the ability to receive signals in two different ways, specific to these networks.

There are quite a large number of smartphone manufacturers offering dual-band products with two SIM cards - these are such giants as Xiaomi, Lenovo, Huawei, HTC and many others. In addition, you can purchase a modem that operates in the desired range.

Hello dear readers. Most cell phone owners only have to worry about one technology called Global System for Mobile Communications or GSM. As the name suggests, this standard has been widely adopted and is used for communication via cellular communications.

But not everyone has jumped on the GSM train. An alternative standard known as Code Division Multiple Access, or CDMA, is also used by many operators around the world. This standard is most popular in the USA and Russia, but is also used in some African and Asian countries, where it competes with GSM.

Here's what cell phone owners should know before purchasing a device that supports one of these technologies.

This is the first question potential owners will ask, and it's a valid one. But in this case there is no simple answer.

GSM and CDMA- these are different ways to achieve the same goal. And the fact that popular networks have been built on the basis of each of them proves that it is not the standard that is important, but the quality of the network. For example, in the US, two of the four largest carriers (Verizon and Sprint) use CDMA, while the other two (AT&T and T-Mobile) have chosen GSM.

From a technical point of view, no standard has an advantage in terms of quality. But there are some things you should take into account. GSM phones can be unlocked and transferred to other operators, and CDMA phones are most often locked to one operator and nothing can be done about it.

In addition, most phones support either GSM or CDMA, so your choice of phone may determine which standard you end up using. Besides that, it all depends on what operators are available in your territory. Some areas are better covered by GSM providers, while in others CDMA providers may have an advantage.

Many phones are compatible with GSM or CDMA, but not both. In the case of CDMA phones, you will have to purchase a device made specifically for your operator. The easiest way is to buy it directly from this operator. For example, if you want to use an iPhone on Verizon's network, you need to purchase a branded iPhone from Verizon, not Sprint or AT&T. However, if you decide to switch to another operator, you will not be able to take the phone with you, as it is locked.

If you don't want to limit yourself to one carrier, you can look for unlocked GSM phones from third-party retailers. Such phones will work with any GSM operator; you just need to change the SIM card. For example, Amazon sells many unlocked GSM phones. The Nexus 5 model from Google and some devices in versions are also unlocked. Any retail or online store that sells cell phones must provide information about what networks each specific device can work with.

Be careful with phone compatibility. Devices sold in markets where both standards operate most often support either GSM or CDMA. Only some phones are compatible with both standards. If you purchased a CDMA phone from a third party retailer, you will have to call your carrier to activate it. If you purchase a GSM phone, you will need to purchase a SIM card and insert it into the device to activate its network capabilities.

CDMA phone owners don't have to worry about SIM cards, but that's a curse rather than a blessing. CDMA devices are mired in compatibility restrictions that are difficult to get around, and GSM phone owners can simply remove the SIM card and replace it with another one. Most CDMA networks will not allow you to use a phone purchased from another operator, even if it is technically compatible. It is very important to remember this limitation when choosing a CDMA network. If you later decide to switch providers, you'll likely have to buy a new phone, even if the network you're switching to also uses CDMA.

Even though GSM is more open, access may still be limited to the frequency range supported by the phone. Frequencies vary from 380 to 1900 MHz and depend on local operators. You should check what frequencies your operator operates on and make sure that the phone you are about to buy supports them. However, GSM is concentrated around four main bands: 850, 900, 1800 and 1900 MHz. A phone that supports all four will work in most countries. This is why GSM phones that are compatible with all major frequency bands are called “world phones”.

If you understand the importance GSM and CDMA, Great! Now let's completely destroy your arrogance by talking about the newcomer, LTE (Long Term Evolution).

LTE is the new standard, which has come into fashion over the past few years. Although it is based on the principles of GSM, it is still a separate standard that operates outside the GSM and CDMA networks. This is truly the fourth generation of cellular data transmission.

LTE is most widespread in South Korea, where the standard is used by most of the market, but it is also popular in Japan, Australia, Sweden and the United States. For now, it is mainly used for data transmission, but LTE can also serve as a replacement for traditional cellular networks. The American company Verizon Wireless, for example, announced its plans to release LTE phones at the end of 2014.

This standard uses SIM cards, so users will be able to switch to other networks, if the device supports them, of course, simply by changing the SIM card. However, now LTE is used mainly for data transmission, not voice. This means that owners of CDMA/LTE phones will still not be able to use other networks. The situation will change when operators like Verizon completely switch to LTE networks. But this may take several years.

Although this standard has great potential, there are obstacles to its adoption. Outside of South Korea, LTE does not account for more than a quarter in any market. South Korea, in general, and Verizon Wireless in the US are actually exceptions to the rule. In most markets, even carriers that offer LTE only offer it in limited areas.

There is also a problem with the spectrum. Remember that GSM/CDMA operate on many different frequencies? The same is true for LTE. You will have to check that your phone is compatible with the frequency bands supported by the operator, and you will not be able to use an LTE phone on another network with the same standard but different frequencies. It is not yet clear whether this standard will become “worldwide” in the same sense as GSM, which settled on four main frequencies supported by most GSM phones.

Summarizing

Take a deep breath. It's time to sum up everything that has been said.

First of all, neither GSM, neither CDMA have no advantage over each other from a technical point of view. They are designed for one purpose, and the quality of the network depends on the operator, not the standard it uses.

Secondly, GSM phones can be unlocked and used with another operator, while CDMA is locked to one operator. It is usually cheaper to purchase unlocked GSM phones than contracted CDMA devices.

Thirdly, you need to carefully check the frequencies supported by the phone. Most are compatible with either GSM or CDMA, and both standards can operate on different frequency bands depending on the region.

Finally, LTE has the potential to become a global standard, but falls prey to even greater frequency division than GSM and CDMA. This technology is relatively new and has not yet been widely implemented.

I hope that cleared everything up. Cellular networks are constantly evolving, and the standards supported by phones may change from year to year. Feel free to ask any questions you have in the comments.

Dessert Iphone 6

Enjoy watching!

https://www.youtube.com/watch?v=jKjXbwPIiHM

Due to the increasing number of questions about CDMA and GSM phones, and the resulting confusion, I will try to explain the difference between them. CDMA phones are cheaper in most cases, and many hope that they will work with Kyivstar, MTS or Life.

I can safely dispel this myth and explain in detail.

About the GSM communication standard

GSM is a communication standard that is actively used by our operators Kyivstar, MTS and Life. These operators have become firmly established in our everyday life, and many buyers use them when buying phones. Because in 90% of cases we buy phones with these particular operators in mind. Let us remind you that the GSM communication standard is based on a frequency division channel range algorithm, using TDMA technology (common frequencies are divided by time), and medium-level security. There are four main GSM frequency bands, and accordingly phones are divided into three groups:

• Single-band - used in a limited number of models, the selection of the desired frequency can be done through a special engineering menu
• Dual Band - operate at frequencies 900/1800 (Asia, Africa, Australia, Europe) and 850/1900 (Canada, USA). Phones have a strict regional locking
• Tri-Band - 900/1800/1900 (Asia, Africa, Australia, Europe) and 850/1800/1900 (Canada, USA).
• Quad-Band - all four bands are used respectively - 850/900/1800/1900. These include all new smartphones released, with rare exceptions.

Services that are available to the user of a GSM phone are voice calls, SMS, fax exchange, roaming (convenient transition from network to network in other countries while maintaining the subscriber's mobile number), packet data exchange using WAP/GPRS/EDGE technologies. You can read about the differences from 3G and setting up mobile Internet in this section . As a disadvantage, GSM operators do not provide 3G Internet and telephony services.

About the CDMA communication standard

The CDMA communication standard has firmly entered the US market as a development of cellular communications, and the name itself denotes the principle of working with frequencies. Each frequency is used at all times by all subscribers; special codes are used for access. It has a high degree of security, which eliminates the possibility of message interception, since the entire spectrum is occupied by noise, and each signal is accompanied by a unique code. A common band allows you to occupy one frequency and serve a larger number of subscribers. Network overload can only cause communication deterioration, but not the possibility of not being able to get through (GSM has this feature). The second feature is quieter and harmless frequencies for the subscriber.

CDMA2000 is a modern communication standard that is actively developing. The frequency used is 1.23 MHz, and the packet data transfer rate is 2 Mbit per second. As you know, the power of the radiation itself is quite weak against GSM (250 mW versus 2W for GSM900). They can also argue that the harm of radiation has not been proven, but there is also no refutation.

To connect smartphones, either a special RUIM card is used, or the phone is simply flashed at the operator’s service center.

Advantages of CDMA?

CDMA phones offer a rather unusual type of service - direct landline number, mobile number, messaging, packet data exchange using CDMA EVDO 3G technology at a speed of 2.3 Mbit per second. Quite loyal tariffs and a convenient option for purchasing a direct landline number make CDMA phones the most attractive in Ukraine. After all, the service of a direct city number for a GSM operator costs an average of 200 UAH per month for call forwarding fees. Here tariffs can be up to 30-50 UAH per month. Operators in Ukraine provide fairly high-quality service to subscribers CDMA Ukraine And Intertelecom.

How to turn on a CDMA smartphone

There is one small inconvenience when buying a CDMA smartphone. You will not be able to check the connection on site at the time of purchase. Since there is no clear SIM card here, and some phones do not even have a slot for connection. Therefore, further activation of your purchase occurs either at the operator’s service center or at its authorized dealer. When purchasing a new CDMA phone, you will be asked to sign a contract and you will be assigned your mobile and landline number (will be offered a choice from the available ones). After successful activation, all services will work on your smartphone. Yes, Intertelecom and CDMA Ukraine services work only under a contract, so be sure to take your passport to connect the phone.

How to check IMEI? He's not there!

We remind you that the IMEI of CDMA phones is not under the control of the Ukrfrequency Supervision database, and when buying a CDMA smartphone, you can be sure that your phone is on the gray, white, black or light green list. That's why CDMA Phones are especially popular. Regarding the lists and the current status of them, you can read

Conclusions:

Now let's take a quick overview of the above:

• CDMA phones operate in other frequencies and are incompatible with GSM operators - KYIVSTAR, LIFE, MTS, UTEL, UkrTelekom
• CDMA phones are serviced only by CDMA communication operators - CDMA Ukraine or Intertelecom
• CDMA phones may not have a slot for an operator card, and more often they are simply flashed to the desired number
• CDMA phones are serviced on a contract basis
• CDMA phones operate in 3G data transfer mode
• CDMA phones provide a free and without forwarding direct landline number in addition to the mobile
• CDMA phones do not have IMEI in the UDCR database lists and cannot be disabled as “gray” or “black”.
• CDMA phones can be much cheaper than GSM analogues