WCDMA what is it? WCDMA or GSM - what's the difference?

WCDMA is Code Division Multiple Access (UMTS). It is a third generation network developed by NTT Docomo and a 2G CDMA network. There are no cell companies that are not based on WCDMA other than Sprint (however, they are slowly converting).

Our world is divided into four different generations of cellular networks:

• 1G - Analog cellular network.
• 2G - GSM or CDMA.
• 3G – WCDMA.
• 4G - LTE, HSPA + all based on WCDMA, Wimax.

VSDMA - standard for 3G network

After the first generation network, providers choose the GSM or CDMA standard for their 2G network. Both of them are incompatible with each other. However, the VSDMA phone will be compatible with the GSM network if it has a SIM slot and is equipped with a GSM antenna.

GSM carrier frequencies are 900 , 1800 , 1900 and 2100 MHz . This is why the iPhone only works on 2G on T-Mobile's network.

In Russia, this technology is used by Beeline and some other companies.

WCDMA Features and Features

The standard is optimized for voice and data communications. Internet access speed reaches 2 Mbit when close to the tower and up to 48 KB when far away. For comparison, GPRS and EDGE technologies in the GSM standard offered a speed of 15-25 KB at best, more often the actual speed was 5-7 or 12 KB. Therefore, an increase in bandwidth provided comfortable access to the Internet, in particular loading pages and content, checking email, etc. In addition, the quality of voice communication has improved due to increased bandwidth.

The WCDMA radio interface uses two channels with a 5 MHz bandwidth. One channel is used to transmit the mobile phone signal to the base station and the other is used to receive the mobile phone signal from the base station. Both channels are at different frequencies, which eliminates the presence of interference and signal overlaps. There are no time or frequency restrictions, as is the case with GSM. Each subscriber receives the entire channel width of 5 MHz.

Since the broadcast of all connected subscribers overlaps, it is important to highlight each subscriber in the general broadcast. For this purpose, code division of the signal is used. The transmitter modulates the signal with a certain numerical code, which is assigned to each user, and the receiver, tuned to a similar code, selects the necessary part of the signal.

What is WCDMA

The abbreviation WCDMA (or W-CDMA) stands for Wideband Code Division Multiple Access, which can be translated as wideband code division multiple access. The WCDMA standard was created as an add-on to GSM, which will operate in the frequency range from 1900 to 2100 MHz, while GSM networks themselves operate in the frequency range from 800 to 1900 MHz.

WCDMA technology is optimized to provide high-speed Internet access and, depending on the distance, provides data transfer rates from 384 Kbps to 2 Mbps. This speed allows you to watch videos, organize video conferences and comfortably surf the Internet. It was WCDMA that was chosen by the majority of mobile operators to provide access to services.

frequency range

The WCDMA network uses three network bands: 900, 1900-2100 MHz. The 900 MHz frequency allows for coverage of up to 10 km, which is approximately half as much as the 2100 MHz frequency. On the other hand, low coverage is compensated by increased network capacity and data exchange capacity. And one base station can serve up to 50 people simultaneously.

The GSM network usually uses a combination of frequencies of 900 and 1800 MHz. The receive and transmit channel widths are typically 25 and 75 MHz, respectively. In some countries, the GSM900 frequency channel width is 10 MHz higher - 35 MHz, due to which the number of frequency channels is 50 more - 174. More often, there are 124 frequency channels of 200 kHz per common channel. And for each frequency channel there are 8 physical channels of 25 kHz, which in turn are divided into a traffic and control channel.

Frequency, physical and logical channels in the GSM network.

A physical channel in GSM can accommodate up to 8 subscribers. More often, up to 5 people hang on one channel, since excess connections noticeably deteriorate the quality of communication. Another 1-2 slots are reserved for service needs. Therefore, if two frequency channels are allocated to the base station, the total number of simultaneously connected subscribers will not exceed 15. If 124 GSM900 frequency channels are used, the simultaneous number of active subscribers will reach 990 people, provided that two channels are reserved. At a frequency of 1800 MHz, the number of frequency channels is 374 or 2990 subscribers, subject to the reservation of two channels.

A comparison of the 900 and 1800 bands clearly demonstrates the expansion of network capacity with increasing frequency. In practice, it is beneficial for operators to allocate several frequency channels for each base station, while placing as many stations as possible. The dense location will allow you to serve more subscribers and improve coverage. And if we consider that WCDMA does not have such significant restrictions, the number of subscribers served is higher compared to GSM.

What is the difference between WCDMA and GSM

GSM is a cellular communication standard that dates back to the late 1980s. It uses frequencies ranging from 800 to 1900 MHz and provides basic cellular services.

For example, using GSM you can:

• Make voice calls;
• Send short text messages (SMS);
• Send fax messages;
• Access the Internet (WAP, GPRS);

In addition, GSM can provide a number of additional services, including: caller ID, call forwarding, call holding and waiting, conferencing, voice mail.

As you can see, GSM provides basic mobile services, while WCDMA is a cellular standard that was created as a complement to GSM. The WCDMA standard operates in the frequency range from 1900 to 2100 MHz and is used to provide access to third generation (3G) mobile communications services.

Also WCDMA and GSM work differently with frequencies and channels. GSM uses time and frequency division (TDMA and FDMA), while WCDMA uses code division (CDMA). Using CDMA has a number of advantages over TDMA and FDMA:

• Efficient use of resources. Code division does not limit the number of possible channels so much.
• High level of protection. The use of code division significantly complicates the selection of a separate channel, since the entire frequency band is almost evenly filled with the signal.
• Save battery power. Phones that work with CDMA have less radiation power, which saves battery power.

Advantages and Disadvantages of WCDMA

Strengths include:

• High Internet bandwidth.
• High-quality communication thanks to the use of the entire channel width of 5 MHz.
• There are no time or frequency restrictions.
• The network capacity is higher, which allows the operator to serve more subscribers.
• Code division of the signal significantly complicates the likelihood of eavesdropping on a conversation or intercepting data.

Weak sides:

• Due to the late introduction of the standard, coverage is inferior to GSM.
• If the coverage is unstable, the mobile device automatically switches to GSM, which speeds up battery consumption.

Advantages and disadvantages

Mentioning the advantages of the WCDMA standard, users talk about advantages over the second generation of communications, which include:

1. Increased Internet bandwidth, up to 42 Mbps when connected to the HPSA+ standard - an option for watching online videos in 720/1080p resolution.
2. Subscribers get the opportunity to use the full 5 MHz channel width. The presence of encryption increases the security of users, reducing the risks of wiretapping or interception of personal data when sending a text message or accessing the Internet.
3. There are no time or frequency restrictions, which reduces the total time spent making a call or sending a message.
4. The expanded network capacity allows the operator to serve a larger number of subscribers - starting from 50 at the base station without allocating additional frequencies. 2Zh has 8 subscribers per channel.

Flaws:

1. Provides less coverage but better call quality.
2. The third generation has not yet supplanted the second, which leads to frequent reconnections of mobile devices between GSM and WCDMA, increasing battery consumption.

Which network mode to choose

In the settings of Samsung smartphones and other Android devices, you can manually set the preferred signal type. This eliminates automatic reconnection between towers. The user has 3 options to choose from:

1. “Only GSM” - the device will work only in 2G networks, connecting to the Internet via GPRS/EDGE.
2. “Only WCDMA” - the device ignores second-generation base stations and searches for towers that support UMTS, increasing the quality of communication and Internet throughput.
3. “WCDMA/GSM” - the device automatically reconnects between two standards, which is affected by the signal level. It is recommended to use it when traveling outside the city limits, where both types of antennas are found. The disadvantage is increased battery consumption.

There is an operating mode with LTE signal detection. It should be disabled if 4G networks are not deployed in your region of residence, thereby saving battery power.

WCDMA is the third generation of wireless networks, which provides a wide communication channel for users, can encrypt transmitted/received data and provides access to the Internet at high speed. It is the preferred option for transmitting information because it consumes less energy.

Conclusion

The article describes in detail what WCDMA is, how it works and the main differences in comparison with GSM. The WCDMA standard is the logical evolution of the cellular network. The technology allows you to serve more subscribers, improve the quality of communication and the speed of Internet access. And the existing developments have made it possible to improve performance in the implementation of UMTS. Despite the dominance of 4G and the active development of 5G, WCDMA remains in demand in some regions where operators have not had time to update telecommunications equipment.

What network do you use? Leave messages in the comments below the article. Please also report if you find an error or inaccuracy in the article.

What is GSM

GSM or Global System for Cellular Communications is the most popular wireless technology used for communication. 2G ) digital cellular networks

It originally started as a circuit switched network, but later packet switching was implemented after the integration of General Packet Radio Service (GPRS)

Widely used GSM frequency bands are 900 MHz and 1800 MHz . Uses a digital radio interface in which analog signals are converted to digital signals before transmission. The packet forwarding speed is 270 Kbps .

Global System for Mobile Communications (GSM) is currently used in approximately 80% of mobile phones worldwide. There are more than three billion users of this technology.

Characteristics of LTE networks

Performance and Throughput

— one of the requirements of LTE is to ensure a peak throughput of the reverse channel of at least 100 Mbit/s.

The technology provides support for data exchange speeds of more than 300 Mbit/s, but the Swedes have already shown us the next stage of LTE development - with a theoretically possible peak throughput of up to 1.2 Gbit/s.

Simplicity

- Supports flexible bandwidth options with carrier frequencies from 1.4 MHz to 20 MHz and frequency division duplex (FDD*) and time division duplex (TDD*).

Delay

Data transmission in LTE is less than in existing 3G technologies. This benefit is critical for serving immersive interactive environments (such as multiplayer games) and sharing large volumes of media content.

Variety of devices

— in addition to mobile phones and peripheral devices, it is planned to equip many computer and consumer electronic devices with built-in LTE modules. These are laptops, tablets, game consoles and set-top boxes, video cameras and other portable devices.

* When using TDD (Time Division Duplex), the entire bandwidth is alternately allocated for loading or uploading data. When using FDD (Frequency Division Duplex), incoming and outgoing traffic are separated by frequency, data is downloaded at one frequency and downloaded at another.

Main performance characteristics

CDMA-450

The introduction of this system became the impetus for the development of new generation cellular networks. The advantage of this standard is that all frequency ranges of mobile cellular communication systems can be fully used here. CDMA phones are already beginning to actively use it (Ukraine is also in the coverage area).

Such networks provide longer communication ranges. This is why operators do not need to build many stations. In the field of providing mobile Internet, there are also a number of advantages over conventional GSM operators. EV-DO technology provides broadband access at speeds up to 2.4 Mbps.

Transmitting data with this system is much safer, because... it uses a special encryption algorithm and cryptographic authentication of all mobile terminals. The technology under consideration will also be useful for ordinary citizens. This is explained by the fact that when the stations operate, the radiation power is 11 times less than from GSM networks.

From all of the above, a completely logical question follows: why are CDMA-450 phones unpopular in Russia and the CIS? There appear to be several reasons:

• Lack of special equipment.
• There is no variety in the models and brands of CDMA phones offered.
• No roaming.

CDMA standards

Despite the fact that this technology is united by the principle of operation, it has several directions. Actually, the CDMA system uses certain sets of channels with a width of 1.23 MHz. In this case, the voice itself is encoded at a speed of 8.55 kbit/s. Sometimes this data stream is reduced to 1.2 kbit/s. This standard is used by the simplest CDMA Nokia phones. Their advantage is reliability and quality.

The CDMAOne standard exists in temporary models IS-95a, IS-95b and J-STD-008. The declared signal speed here ranges from 9.6 kbit/s to 115.2 kbit/s. These networks appeared back in 1995 in America. The standard is now quite common in Asia. In Russia, only certain fixed-line communication services are allowed to be provided through such a system.

The CDMA2000 standard is the successor to CDMAOne. It almost completely corresponds to the 3G generation. Another feature and value of it is that it is on the basis of this standard that new systems of cellular operators are developed.

Disadvantages of CDMA

Despite the obvious advantages over the GSM standard, these networks are actively used only in America. Europe is just beginning to get acquainted with this technology. Among the shortcomings that hinder the rapid and confident promotion of CDMA to the masses are the following:

• Price. Despite quite reasonable tariffs for direct city numbers, such phones are more expensive than their GSM counterparts.
• Repair. Due to the fact that such gadgets are not common in the world, spare parts are quite difficult to find. In addition, not everyone is familiar with repair technology.
• Lack of base stations on a CDMA phone. What is it? These are telecommunication points that provide network coverage.

Advantages of the CDMA standard

This technology is quite new. And it is in many ways inferior to that used by GSM cellular operators. It has undeniable advantages:

• Confidentiality and security of personal information. Thanks to the encoding technology used, the user is almost completely protected from various fraudulent activities. In addition, extraneous noise and the possibility of parallel conversations are completely eliminated here.
• Less energy consumption. Due to optimized data transmission, CDMA-450 phones consume battery power much more slowly. This could allow manufacturers to create models that are much more compact and ergonomic.
• There are practically no interrupted conversations. CDMA phones significantly increase call capacity and eliminate busy and parallel lines.
• Extended network coverage area. CDMA uses completely different telecommunication technologies, which can significantly increase the coverage area.
• Additional services. This could be the transmission of operational important data and messages, identification of any subscriber, etc.

WCDMA network mode

To use the “WCDMA Only” mode, you need to open the smartphone settings and select the appropriate item. Soon the phone will automatically connect to the third generation network. It allows you to make voice calls and use the Internet at good speed. Typically, the data transfer speed reaches 3 Mbit/s, but for this it is recommended to ensure ideal conditions - go out into the open to avoid any obstacles between the smartphone and the operator’s repeater.

WCDMA mode is ideal for mobile Internet users. It allows you to freely view streaming video and quickly load even “heavy” sites. It is important to take into account that the third generation of communications drains the phone’s battery faster and can even heat up the case (compared to 2G).

GSM mode

By selecting GSM network mode in the phone settings, the user enables the main communication standard supported by cellular operators. It belongs to the second generation and handles voice calls well. An additional advantage is wide coverage - you can catch the operator’s signal almost everywhere, even in remote settlements. Moreover, the phone will work much longer than with WCDMA enabled.

The disadvantage of GSM is the low Internet speed. When choosing GPRS technology, the information transfer speed will fluctuate around 171 kilobits per second. If the user turns on EDGE Internet, it will be possible to reach speeds of up to 474 kilobits. This indicator is only suitable for viewing optimized sites - you can check the weather or news, read informational articles, check email or chat in instant messenger. You won't be able to download a large file or watch a streaming video.