The presence of lte. Availability of VoLTE support by the operator

Cellular networks of the GSM standard in their structure were not originally intended for mobile internet. Accordingly, today, cellular operators are forced to invest huge amounts of money in upgrading their networks to 3G (UMTS), and now to 4G (LTE) in order to meet the needs of the population. Of course, the cellular companies generously borrow these investments from our pockets, but their work is also not very easy.

Now, when the introduction of 3G networks in Russia has not yet been completed, operators have already begun work on next-generation networks - 4G or LTE.

The photo shows the first LTE base station from Yota in Sochi:

The term LTE itself stands for Long Term Evolution and translated into Russian means "long-term evolution". For a long time, the WiMAX standard claimed the role of 4G communication, but was subsequently relegated to the background as a less popular option for fast wireless Internet.

LTE is the next generation of mobile communications after 3G and operates on the basis of IP technologies. The main difference between LTE and its predecessors is the high data transfer rate. Theoretically, it is up to 326.4 Mbps for receiving (download) and 172.8 Mbps for transmitting (upload) information. At the same time, the international standard indicates the figures of 173 and 58 Mbps, respectively. This fourth generation communication standard was developed and approved by the 3GPP International Partnership.

Latest generation coding system - OFDM

Let's figure out what is main feature LTE standard. As well as in 3G networks, OFDM-MIMO coding and data transmission technology can be called the main link in LTE.

OFDM stands for Orthogonal Frequency-division Multiplexing and in Russian means orthogonal frequency division of channels with multiplexing. This is a digital modulation scheme using a large number of closely spaced orthogonal subcarriers. All subcarriers are modeled with a standard modulation scheme such as QAM at a low symbol rate while respecting the overall data rate as in simple single carrier modulation schemes in the same bandwidth. In fact, OFDM signals are generated through the application of "Fast Fourier Transform".

This technology describes the direction of the signal from the base station (BS) to your mobile phone. As for the reverse signal path, i.e. already from the telephone set to the base station, technical developers had to abandon the OFDM system and use another technology called SC-FDMA. In decryption, it is read as Single-carrier FDMA and in translation means multiplexing on a single carrier. Its meaning is that when adding a large number of orthogonal subcarriers, a signal is formed with a large crest factor (the ratio of the signal amplitude to its RMS value). In order for such a signal to be transmitted without interference, a high-quality and rather expensive high-line transmitter is required.

It was this device that created some difficulties in obtaining a license in Russia for LTE networks. And, nevertheless, as is usually the case in our country, despite the artificially created difficulties, the Russian Ministry of Communications recognized promising direction development of cellular networks is the LTE standard. However, when tendering for distribution, often 2.3 - 2.4 GHz in 40 regions Russian Federation only OFDMA technology was indicated as a radio access method, which excludes, directly, LTE, since. in the latter case, in addition to OFDMA, SC-FDMA is also needed. From this once again follows the complete incompetence of Russian officials in the matters they deal with.

MIMO- Multiple Input Multiple Output is a technology for transmitting data using N-antennas and receiving information with M-antennas. In this case, the receiving and transmitting antennas are separated from each other by such a distance as to obtain a weak degree of correlation between adjacent antennas.

LTE position on the air

On the this moment frequency bands are already reserved for 4G networks. The most priority is considered to be frequencies in the region of 2.3 GHz. The main example here is China with its mobile operator China Mobile, which has already allocated the required frequency range and is conducting test broadcasts. Given the huge volume of local cellular consumption, the use of this frequency is doomed to success and dominance in China.

Another promising frequency range - 2.5 GHz is used in the US, Europe, Japan and India. There is also a frequency band around 2.1 GHz, but it is relatively small - only 15 MHz are available in the 2.1 GHz band, and most European mobile operators limit bands up to 5 MHz in this range. In the future, the 3.5 GHz frequency band is likely to be the most used. This is due to the fact that wireless broadband Internet access networks are already used on these frequencies in most countries, and thanks to the transition to LTE, operators will be able to use their frequencies again without having to purchase new expensive licenses. If necessary, other frequency bands can be allocated for LTE networks.

With regard to the frequency bands used and distribution methods in LTE, everything is rather unclear and contradictory, because the standard itself is quite flexible. In different structures, fourth generation networks can be based on frequency bands in the range from 1.4 to 20 MHz, in contrast to the fixed 5 MHz in 3G (UMTS). It is also possible to use both TDD (Time Division Duplex) and FDD (Frequency Division Duplex) signals. For example, the LTE network being built in China is of the TD-LTE standard.

The coverage area of ​​an LTE base station can vary. Usually it is about 5 km, but in some cases it can be increased to 30 or even 100 km, in the case of a high location of the antennas (sectors) of the base station.

Another positive difference of LTE is a large selection of terminals. Apart from cell phones, many other devices such as laptops, tablets, gaming devices, and camcorders that have built-in LTE support will be used on LTE networks. And since LTE technology has support for handover and roaming with previous generations of cellular networks, all these devices will be able to work in 2G / 3G networks.

The structure of fourth generation networks

The scheme of 4G (LTE) networks is as follows:

As can be seen from this diagram, LTE networks include 2.75G (EDGE) and 3G (UMTS) network modules. Because of this feature, the construction of fourth-generation networks will be quite specific and look more like the next stage in the development of today's technologies than something fundamentally new.

For example, according to such a structure, a call or an Internet session in the coverage area of ​​an LTE network can be transferred to a 3G (UMTS) or 2G (GSM) network without interrupting the connection. In addition, LTE networks are fairly easy to integrate with WI-FI networks(WLAN Access NW in the diagram above) and the Internet.

Let us dwell on the radio access subsystem in more detail. In its structure, the RAN radio access network - Radio Access Network - looks similar to the UTRAN UMTS network, or eUTRAN, but has one addition: the transmit and receive antennas of base stations are interconnected according to a specific X2 protocol, which combines them into a cellular network - Mesh Network - and makes it possible base stations to communicate directly with each other without using the RNC - Radio Network Controller for this.

In addition, the interconnection of base stations with the MME mobile device management system - Mobility Management Entity - and service gateways S-GW - Serving Gateway - is carried out by "many-to-many", which allows you to get a high speed of communication with low delays.

LTE vs. WiMAX

Surely many of you wondered why the future is for LTE? After all, just a year or two ago, everyone considered the 4G standard to be WiMAX technology, well known by such broadband wireless Internet providers as Yota and Comstar.

In fact, the LTE and WiMAX standards are quite close to each other. They both use OFDM coding technology and MIMO data transmission system. Both standards use FDD and TDD duplication for channel bandwidths up to 20 MHz. And both of the communication systems use IP as their protocol. Accordingly, both technologies in reality equally well use their frequency range and provide a comparable data transfer rate of Internet access. But, of course, they also have some differences.

One of these differences is a much simpler WiMAX network infrastructure, and, consequently, more reliable technically. This simplicity of the standard is provided by its designation exclusively for data transmission. On the other hand, the "complexities" of LTE are needed to ensure its compatibility with the standards of previous generations - GSM and 3G. And we will definitely need this compatibility.

There are other details in the difference between LTE and WiMAX. For example, scheduling of radio frequency resources. In WiMAX, it is produced using Frequency Diversity Scheduling technology, according to which the subcarriers provided to the subscriber are distributed over the entire spectrum of the channel. This is necessary to randomize and average the effect of frequency selective fading on a wideband channel.

LTE networks use a different technology to eliminate frequency-selective fading. It's called Frequency Selective Scheduling. At the same time, for each subscriber station and each frequency block of the carrier, channel quality indicators CQI - Channel Quality Indicator are created.

Another very important point associated with the planning of communication networks for mass use - frequency reuse factor. Its role is to show the efficiency of using the available radio frequency band for each base station separately.

The basic structure of WiMAX frequency band reuse consists of 3 frequency channels. When using a three-sector configuration of sites (base stations of a certain frequency range), one of the 3 frequency channels is implemented in each of the sectors. In this case, the frequency reuse factor is equal to 3. In other words, at each of the points in space there is only a third of the radio frequency range.

The operation of the LTE (4G) cellular network is performed with a frequency reuse factor equal to 1. That is, it turns out that all LTE base stations operate on the same carrier. Intra-system interference in such a system is minimized by frequency selective scheduling, flexible frequency scheduling, and inter-cell interference coordination. Subscribers in the center of each cell can be given resources from the entire free channel bandwidth, while users at the edges of the cells are given frequencies only from certain subbands.

The features of LTE and WiMAX networks listed above have a great influence on one of their main characteristics - the degree of radio coverage. Based on this parameter, it is determined required amount base stations for high-quality coverage of a specific area. Accordingly, it directly affects the final cost of building LTE networks.

According to the calculation, the LTE network is able to provide best zone coverage with the same number of base stations, which is a definite plus for all mobile operators.

Nowadays, the question of LTE is often asked - what is it in a phone? Modern manufacturers of devices and equipment for mobile communications are preparing the industry for a new breakthrough - the transition to the 4G communication standard. The possibilities of this standard are simply fantastic. Theoretically, 4G will provide Internet speeds of up to 100 Mbps for mobile communications in motion and up to 1 Gbps for stationary ones. It's 100 times more powerful modern format 3g. Leading manufacturers are already equipping 3G phones with support for the "next generation" standard - LTE.

LTE - what is it?

Implementing a new mobile communication standard is not easy or quick. The introduction of the two previous formats took a decade each. Work on 4G began in 2008, but even now, when asked what LTE is, it can be answered that this is the first stage in the development of the 4G format. This technology allows you to increase not 100, but 10 times, but this is only the first generation of the format. The technology is rapidly popularizing and is of interest to more and more users.

LTE and 4G - what's the difference?

It is too early to say that the high bar set by the developers of the 4G communication standard will be overcome very soon. Apparently, there are still a few years before the mass transition. But the first steps have already been taken, and they have shown significant advantages over 3G. Modern technology LTE is a high download speed on a mobile device, and a huge upgrade in the hardware that makes it work. wireless networks and their infrastructure. And this will allow in the near future to increase the possibility of data exchange without the use of wired networks.

Benefits of LTE

The latest models of smartphones equipped with LTE technology provide the subscriber with the opportunity to use high-speed Internet. This transitional technology, in practice, provides 100 Mbps when receiving and 50 Mbps when uploading. At the same time, it must be remembered that the actual indicators are always lower than the calculated - theoretical ones. High speed LTE provides users with the following features:

• to carry out two-way video communication with high quality;
• watch videos online in FullHD format;
• use any service programs and much more.

How to connect LTE?

The latest iPhone models, starting with the iPhone 5, are equipped with an LTE module. The capabilities of the module are expanding in each new generation, and if for the iPhone 5, 5c, 5s the exchange rate was 100 Mbps, then in the iPhone 7, 7 Plus it is already 450 Mbps. In order to take advantage of this technology, you should answer the question - how to enable LTE. The instructions are simple and look like this:

1. In the Settings menu, select Cellular, then Data Options and Voice.
2. Check the box next to LTE. Select "Enable LTE" in the pop-up message box
3. To check the connection speed, it is convenient to use the free Speedtest utility.

Why is LTE not working?

If the LTE module is not working, then there may be several reasons for this. Often this problem occurs because there is no support for LTE coverage by your network operator. If these problems are at the software level, then you can deal with the problem yourself. First, you should go to Settings and check the connection. If the connection is made, but the module does not work, you can try to solve the problem using the following algorithm:

1. Reset the device and reboot it. Service information will be updated, and data, except for Wi-Fi passwords, will be deleted.
2. You will need to install the latest IOS update on your device.
3. Reboot the device again - Reset by holding the power button, then select "home" and hold at the same time until the download indicator lights up.

Technology does not stand still, and this is especially noticeable in the segment of mobile devices and communications. New gadgets set higher standards and give rise to new needs and requirements, first of all, in the quality of mobile communications and the speed of information transfer. One of the most interesting and promising areas today is the fourth generation of 4G communications, which, in theory, should provide increased quality of voice communication and a much higher speed on the Internet.

How is 4G different from previous generations of communication?

To understand the differences and advantages of the LTE standard and whether there is any point in a large-scale transition to 4G, you need to consider the key differences between this format and its predecessors, starting from the very first generation. Such was analog communication, which was actively used until the end of the 90s. Huge by today's standards, communications equipment in special cases-suitcases with a total weight of up to 5-7 kilograms - they worked on this standard.

With the introduction of second-generation communications, the mobile device market has undergone a real revolution. Most ordinary users know this standard under the name GSM. There was an opportunity to connect to the Internet. The format remains popular and widely used today.

Third generation communication has qualitatively changed the idea of ​​network speed on mobile devices. 3G includes several wireless technologies, the most popular of which are UMTS, EV-DO and CDMA2000. In theory, the maximum download speed should be 21 Mbps. In practice, these figures rarely even reach 5 Mbps. Watching online video, of course, is not very comfortable, but in most cases it is enough for ordinary surfing the Internet. Definitely faster than the same EDGE, and this, in the absence of an alternative, is very pleasing.

As for 4G, there is still no officially approved full-fledged network of this format in the world. In order for an authorized organization to officially “recognize” this protocol, it is necessary that it provide data transfer at incredible speeds compared to previous generations of communication: 100 Mbps for mobile electronics and 1 Gbps for stationary devices with the ability to access the Internet. The most promising technologies, which, with a competent approach, have every chance of being called a full-fledged 4G, are the WiMAX and LTE protocols.

Main features and characteristics of the LTE standard

The principle of LTE technology becomes well understood from the decoding of this abbreviation: “Long Term Evolution”. In literary translation into Russian given expression means "long-term development". Companies involved in the development of the standard take into account all the errors and failures of the transition from one communication format to another. As practice shows, main problem is to ensure the compatibility of new technologies with old equipment and, of course, the costs required for a full transition.

In theory, LTE cells will be able to provide the highest quality communication at a distance of up to 100 km. This is especially true for remote and sparsely populated areas. For comparison, the maximum for the most common communication format today is a distance of 30 km. That is, it will be much more profitable for mobile communication companies to install one 4G point than several 3G or GSM towers.

The new format should provide more high quality connection head. GSM and 3G networks transmit voice in the band up to 3.5 kHz, which is a rather modest indicator. Modern technologies will be able to transmit voice in full mode, i.e. from 20 Hz to 20 kHz. In practice, this should provide the most believable and realistic sound, as if the interlocutor is not talking on the phone, but is nearby.

At present, experts various countries active work is underway to improve and develop the communication format, experts are gradually approaching the previously mentioned data transfer rates. At the moment, the maximum that has been achieved is 173 Mbps for downloading information from the network and 58 Mbps for uploading. In practice, these figures are often reduced to 10 or more times, but even in such conditions, the “inferior” 4G is confidently superior in speed to third-generation communications.

LTE is a mobile wireless communication standard that has been wide use in 2010. The new standard of the fourth generation, which replaced 3G, marked the beginning of an era of really fast and reliable mobile Internet. 4G allowed users, using smartphones, not only to easily open almost any site, even loaded with a variety of content, but also to fully use Skype, view videos of any quality through them. The presence of a high-quality Internet connection of the fourth generation wireless mobile communication standard is based on the fact that 4G LTE uses orthogonal frequency control (in the radio channel), and is based on IP technologies at the network level.

Specifications and features of 4G LTE

The carrier frequency of the bandwidth of 4G networks is in the region from 1.4 MHz to 20 MHz. Compared to the previous 3G standard, 4G LTE has lower latency in data transmission, which is an extremely important factor when exchanging significant amounts of media content.

Bandwidth

A distinctive feature of 4G LTE is the provision of a peak reverse channel bandwidth of more than 100 Mbps. Theoretically, the fourth generation standard can provide Internet speeds up to 300 Mbps.

Work speed

The presence of an Internet speed of at least 100 Mbps, as well as a speed of more than 300 Mbps provided by the standard, largely depends on the congestion of networks and on the location of the subscriber. At the same time, the possible incoming Internet speed (LTE Advanced) can be up to 3 Gb / s, and outgoing up to 1.5 Gb / s.
Switching from LTE to LTE Advanced is easy. To do this, you just need to update software and change carrier base stations.

Advantages

Support for 4G LTE networks by a smartphone will provide the user with inexpensive traffic and reliability of the communication channel, provide high throughput and reduce delays.

Best 4G LTE Smartphones

1. One of the best smartphones supporting 4G standard is samsung galaxy S4, which is the leader in sales among devices running on the Android platform. In addition, its reduced version (Mini) also retained support for LTE, without reducing the functionality and speed characteristics.
2. Another great 4G LTE smartphone is HTC One. The presence of a presentable appearance and powerful functionality is perfectly complemented by fast and reliable LTE Internet.
3. From the representatives of Nokia, an excellent model that supports the ability to use 4G networks is Nokia Lumia 925. This is one of the best smartphones running on operating system Windows. 4. One of the best representatives in the smartphone market is certainly iPhone 6. The availability of 4G LTE networks, including for residents of Russia, along with powerful functionality put it on a par with the most popular phones in the world.
5. It is worth noting such a business smartphone as BlackBerry Q10. Having slightly lost its positions, it still remains a very popular phone with 4G LTE network support and a QWERTY keyboard.