Menu
homeInternet

CDMA communication standard: detailed characteristics. GSM and CDMA: What is the difference and which is better? Telephone with two standards gsm and cdma

This material will look at CDMA phones, what kind of devices they are and in what cases you simply cannot do without them. The characteristics of real models will also be indicated and recommendations regarding their purchase will be given.

Two main mobile communication standards

Currently, mobile devices of two standards are most widespread: GSM and CDMA. Each of them is a digital standard. But signal transmission in each of these cases is carried out differently. In the first case, it is divided into parts, each conversation occupies only a small part of the spectrum. In the second case, encoding allows the subscriber to use the entire radio frequency resource. As a result, in this case the quality of communication is an order of magnitude better. But today devices for mobile networks of the first type have become more widespread. This standard was introduced much earlier and was already in active use at the time of the announcement of CDMA solutions. Now we will get an answer to the question: “CDMA phones - what kind of devices are these?” These are devices that are designed for use in mobile CDMA networks. Similarly, GSM solutions are used only in such cellular networks.

Supported devices

There are many devices designed to function in it. First of all, these are mobile phones of the appropriate standard. They have a relatively low level of functionality: conversation, text and multimedia messages. In some cases, this list can be expanded by data transfer. So the answer to the question: “CDMA phones - what are they?” - is the definition: “This is a device that allows you to make calls, send and receive text or multimedia messages, or connect to the Internet on CDMA networks.” The second type of device that can be used in such networks is modems. They can perform only one task - to transmit and receive data from the World Wide Web to a PC. Another type of device is mobile Wi-Fi routers. They do the same thing as modems, but in this case, a computer is not necessary to make the connection. The router creates a wireless computer network to which any device with a Wi-Fi transmitter can be connected. The last type of device is smartphones. These are mobile devices whose capabilities are expanded through the use of special software. In this case, you can watch videos, listen to music, and communicate on social networks... You can even use it as a mobile Wi-Fi router.

Operators in Ukraine

Until recently, there were quite a lot of cellular operators in Ukraine that operated using this standard. This includes Velton, Ukrainian Wave, People.net, and Intertelecom. But now only the last two continue to provide services. The first two of them were acquired by Intertelecom, their subscribers joined its cellular network. In turn, People.net, due to economic difficulties, began to “wind down” its coverage, because of this, many of its subscribers were forced to switch to its direct competitor, Intertelecom, which then became the only national CDMA operator. The basis of its subscriber base is made up of dual-standard CDMA-GSM phones. Odessa is the city from which this operator began its victorious march across the country. Now its coverage covers most of the country. So owners of CDMA devices can work in Ukraine only on one cellular network.

"Lenovo A330e"

The 5-inch display diagonal and affordable price are the main advantages of this model. The hardware basis of the device is Snapdragon 200 with two computing modules. Each of them can theoretically be overclocked to 1.2 GHz. The memory subsystem is represented by 512 MB of RAM and 4 GB of integrated data storage. The capacity of the included battery is 2000 mAh, which is definitely enough for 2 days of use. The operating system in this case is Android. The price for this device starts at 6,000 rubles.

Huawei Y321C

One of the most affordable devices of this standard is the Huawei Y321C CDMA phone. Although this is already a smartphone that runs Android. Its computing basis is the 2-core Snapdragon MCM8625 with a peak frequency of 1 GHz. RAM is 0.5 GB, and the capacity of the built-in storage is a “modest” 4 GB. The display diagonal is only 4 inches, and its resolution is 480x800. A battery with a capacity of 1350 mAh is responsible for autonomy. This is definitely enough for 1 day of work. The price for this device is 5,750 rubles.

"Lenovo A805e"

This is the most affordable GSM-CDMA mobile phone with a diagonal of 5.5 inches at the moment. Its main computing power is the 4-core Snapdragon 410 CPU. Each of its computing modules can increase its frequency up to 1.2 GHz. Comfortable operation on this device is ensured by 1 GB of RAM and 8 GB of integrated storage. A 2500 mAh battery is responsible for autonomy; this is quite enough for 1-2 days of battery life. The price of this gadget is 8,000 rubles.

HTC T329d

HTC also has solutions for this digital standard. CDMA-standard phones from this manufacturer, although not so often, can still be found. One of the most affordable models is the HTC N329d. Like all previously reviewed gadgets, this smartphone is dual-band and can operate simultaneously in both a CDMA network and GSM coverage. At the heart of this device is a 2-core CPU that can dynamically accelerate to 1 GHz. The amount of RAM is 768 GB, and the built-in storage capacity is 4 GB. Screen diagonal - 4 inches. The resolution of 800x480 allows you to display the output image with sufficient quality. The battery capacity allows you to count on 2 days of battery life without recharging.

The device is equipped with a variety of wired and wireless methods of transmitting information that allow you to fully realize its potential. You can buy such a device now for 7,500 rubles.

Summary

This article answered the question: “CDMA phones - what are they and what are they for?” The characteristics and cost of real models of this type of device, as well as mobile operators that provide services in this standard in Ukraine, are also indicated. Any of the above models will be an excellent purchase and will allow you to communicate and receive data from the Internet.

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.

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

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