What is wimax internet. Wireless internet wimax. User equipment

Today technology wireless WiMAX is the most advanced of all. Appearing back in 2003, it was aimed at satisfying the broadcast market.

Around the world, a large number of operators have started building wireless networks. Such networks exist now in the USA, Japan, Korea, Russia and many others. Taking into account the words of leading analysts in the field of communications, WiMAX will soon have more than 100 million network users.

Today we can safely say that WiMAX has no alternative technology, which makes it an advanced product. In this article, we will take a closer look at the features of this technology, its advantages and disadvantages.

What it is?

"WiMAX" ("International Interaction for Microwave Access") is a technology developed in 2003 with the aim of providing wireless connectivity for workstations, stationary computers, laptop computers and mobile devices... Based on the "IEEE 802.16" communication standard.

What tasks does WiMAX solve:

  • providing broadband communications instead of leased lines and "DSL / ADSL";
  • providing remote monitoring systems;
  • creating points remote access that are not tied to a geographic location;
  • provision of Wi-Fi access points and their connection with each other, as well as other zones of the Internet network.

I would also like to briefly talk about the main stages of the development of this technology:


Scope and feasibility of application

Today developers all over the world are facing the problem of the "last mile" (the channel that connects the user's end equipment with the provider's access point). Fortunately, there are now many varieties of last mile technology that make it easy for any provider to choose this technology.

Today the problem of the last mile does not have a clear and universal solution. Absolutely every existing technology has its own area of ​​application, pros and cons.

The choice of a particular technology can be influenced by a large number of factors, and here are the main ones:

  • way to achieve the set goals, efficient use of resources, target audience,
  • allocation of investments that will subsequently go to the development of the network;
  • availability and operability of the existing network infrastructure, as well as certain resources that will be used to support the technical operation of the network.

Each of the above factors plays a special role in the selection of a technological solution.

I would also like to note, comparing Wi-Fi and WiMAX, that the latter allows users to access the Internet at a fairly high speed. The coverage of WiMAX networks is much greater than that of Wi-Fi.

video: WiMax technology

Technology options

The entire family of WiMAX technology has a fairly wide range of advantages, which have certain differences from each other. Developers of WiMAX technology tried to find the most appropriate option for mobile and fixed use.

However, it is worth noting the fact that the combination of requirements within the framework of one standard is still an unsolved problem. The standard requirements are completely similar to each other, but at the same time, each technology has a specific focus on different areas of the market. Therefore, this was the impetus for creating two separate versions of the standard.

Photo: IEEE 802.16 e and d technology

Each WiMAX specification has its own technical characteristics: emission powers, frequencies, access and transmission, reuse radio frequencies. And it is precisely because of these features of the WiMAX systems, based on the IEEE 802.16 e and d standards, that they have practically no compatibility.

  • 802.16-2004 - Was approved in 2004. During operation, frequency multiplexing is used. In addition, there is support for the so-called fixed access in those areas where there is no line of sight. In most cases, the frequencies used are 3.5 and 5 GHz.
  • 802.16-2005 - was approved in 2005. A new version is a big step in the evolution of fixed access. The new version has received support for mobile subscribers, and its distinctive feature is the support of a number of special functions, such as: "Idle mode", "Handover".

Distinctive features between the two specifications are that only static subscribers work due to fixed WiMAX (802.16-2004), and when 802.16-2005 (mobile WiMAX) work, subscribers who move at speeds of up to 110 kilometers per hour work.

I would also like to note that due to mobility, all roaming functions and the so-called "seamless connection" between the main workstations are provided while the subscriber is on the move. There are also exceptional cases when 802.16-2005 can be used quite well when serving static subscribers.

I would also like to note that most companies give their preference to WiMAX, providing high-speed communication services.

And there are reasons for this:

  • first of all, 802.16 is effective from an economic point of view when providing its customers with access to the network, as well as expanding services and covering new territories;
  • secondly, it is ease of use, in contrast to wired channels. WiMAX and Wi-Fi are fairly easy to use, deploy, and of course scale up. Enough convenient way when creating enough large network in the shortest possible time.

WiMAX subscriber equipment

Currently, equipment for using WiMAX networks can be installed indoors (such devices are usually no larger than traditional DSL modems) and outdoors (laptop-sized devices).

Indoor devices are more convenient to use, but can only work on short distances from the base station.

Because of this, equipment that is installed indoors requires a larger investment, since a large number of access points will be required to ensure quality work.

Working principle and concepts

WiMAX consists of the following elements: stations (base and client), equipment that is a link between stations, an Internet network. For the connection between the base station and the client, frequencies from 2 to 11 GHz are used.

Line-of-sight is usually established between base stations and an operating frequency range of 10 to 66 GHz is used. The line of sight between workstations and the frequency range allow for data exchange rates of up to 120 Mbps. But at the same time, one of the workstations must be connected to the provider's network using the standard wired connection method.

Standards IEEE 802.16 has a GSM network structure. The range of base stations in several kilometers and the construction of any additional towers that amplify the signal is absolutely not required.

Modes

The wimax 802.16e-2005 standard includes all versions that were released earlier:


MAC / link layer

In 802.16 MAC networks, a so-called scheduling algorithm is used. Operating principle this algorithm is based on the following: absolutely any client station can connect to the access point, and after connecting, a separate slot will be automatically created for it directly on the access point. In addition, other users cannot influence this and thus it excludes a disconnection.

WiMAX Architecture

At the WiMAX Forum, an architecture specification was created, thanks to which it is possible to define a huge number of nuances of work. This number includes the distribution network addresses, interaction with other networks, authentication.

I would like to note that the network architecture is not strictly tied to a particular configuration, therefore, a fairly high flexibility and scalability is provided.

Advantages and disadvantages

The benefits include:


The disadvantages include I am:

  • shortage of frequency devices;
  • unpreparedness of the legislative base;
  • difficulties in implementation new technology, which is why at the moment there is no possibility of providing high-quality communication at a low cost.

In this article, we took a closer look at WiMAX. It's safe to say that WiMAX is currently the leading wireless technology. Today it has gained quite wide popularity in the modern world.

System WiMAX consists of two main parts.

    Base station WiMAX, can be located on a high-rise object: a building or a tower.

    Receiver WiMAX: antenna with receiver, in the form factor of a PC Card, a PC expansion card or an external card.

The connection between the base station and the client receiver is made in the 2-11 GHz range. This connection allows data transfer at speeds up to 20 Mbps and does not require line-of-sight between the station and the user. Technology WiMAX it is used both on the “last mile” and to provide access to regional networks: office, district. A permanent connection is established between neighboring base stations using the microwave (super-high frequencies 10-66 GHz) line-of-sight radio communication. This connection, in ideal conditions, allows data transfer at speeds up to 120 Mbps. The line-of-sight constraint is not a plus, but it only applies to base stations participating in the integral coverage of the area, which is quite possible to implement when placing equipment.

Rice. 2.1 - Organization of a communication network using WiMax technology.

At least one of the base stations can be permanently connected to the provider's network via a high-speed broadband connection. In fact, the more stations have access to the provider's network, the higher the speed and reliability of data transmission. However, even with a small number of points, the system is able to correctly distribute the load due to the cellular topology.

On the basis of the cellular principle, the construction of an optimal network is also being developed, enveloping large objects (multi-storey urban buildings, mountain ranges), when a series of successive stations transmits data according to the relay principle.

Rice. 2.2 - Diagram of the organization of a regional network using WiMAX technology.

In terms of structure, the IEEE 802.16 standard networks are very similar to traditional mobile communication networks: there are also base stations that operate within a radius of up to 50 km, and they also do not have to be installed on towers - roofs of houses are quite suitable for them, you only need to comply with the condition of a straight line visibility between stations. To connect the base station with the user, subscriber equipment is required. Further, the signal can go through a standard Ethernet cable, either directly to a specific computer, or to an 802.11 Wi-Fi access point or a local wired Ethernet network.

2.3. WiMax operating modes.

The 802.16e-2005 standard has incorporated all previously released versions and currently provides the following modes.

    Fixed WiMAX- fixed access;

    Nomadic WiMAX- session access;

    Portable WiMAX- access in the move mode;

    Mobile WiMAX- mobile access.

Fixed WiMAX ... Fixed access is an alternative to broadband wired technologies (xDSL, T1, etc.). The standard uses the frequency range 10-66 GHz. This frequency range, due to the strong attenuation of short waves, requires a line of sight between the transmitter and the receiver of the signal. On the other hand, this frequency range avoids one of the main problems of radio communication - multipath signal propagation. At the same time, the width of communication channels in this frequency range is quite large (a typical value is 25 or 28 MHz), which makes it possible to achieve transmission rates up to 120 Mbit / s. Fixed mode was included in the 802.16d-2004 version and is already in use in a number of countries. However, most companies offering services FixedWiMAX, expect an early transition to portable and in the future mobile WiMAX.

Fig 2.3. - Networking in Fixed WiMAX mode.

Nomadic WiMAX ... Session (nomadic) access added the concept of sessions to the existing one FixedWiMAX... The presence of sessions allows you to freely move client equipment between sessions and restore the connection using other base stations WiMAX than those used during the previous session. This mode is designed mainly for portable devices such as laptops, PDAs. The introduction of sessions allows you to reduce the power consumption of the client device, which is important for portable devices.

Portable WiMAX ... For mode PortableWiMAX added the ability to automatically switch the client from one base station WiMAX to the other without losing the connection. However, for this mode, the speed of movement of the client equipment is still limited to 40 km / h. However, already in this form, you can use client devices on the road (in a car when driving through residential areas of the city where speed is limited, on a bicycle, walking, etc.). The introduction of this mode made it expedient to use the technology WiMAX for smartphones and PDAs. In 2006, the release of devices operating in portable mode began WiMAX.

Mobile WiMAX was developed in the 802.16e-2005 standard and allowed to increase the movement speed of client equipment to more than 120 km / h.

Fig 2.4. - Networking in Mobil WiMAX mode.

The Hybrid-Automatic Repeat Request (H-ARQ) technology used in this mode allows maintaining a stable connection during a sharp change in the direction of movement of the client equipment. And the Network-Optimized Hard Handoff (HHO) technology allows up to 50 milliseconds or less to reduce the time for switching the client between channels.

WiMAX is a relatively new radio communication technology. It is designed for building wireless local area networks (WLAN) and provides broadband user access to this network and Internet resources. Another, much more familiar way of organizing WLANs is Wi-Fi. Because of this, some confusion often arises: the new technology is considered an improved version of the old one. And the name itself - WiMAX - evokes certain associations with Wi-Fi technology. But still, the differences between them are quite serious.

The history of WiMAX

By the end of the last century, there were many proprietary solutions for deploying global wireless networks... The devices targeting each solution clashed with each other, and the network was too expensive to build. These problems could be overcome only by getting rid of the closed formats, which was done in 1999. Largest manufacturers telecommunication equipment together with the IEEE association agreed to develop a single standard for wireless broadband communications. This is how IEEE 802.16 appeared, and in 2001 the organizations developing it formed the WiMAX Forum. At the same time new standard and named after this consortium.

First, on the basis of the new technology, backbone data transmission channels are created, replacing the usual "dedicated lines" and DSL connections. Wi-Fi, on the other hand, with all the variety of options for organizing local wireless networks, is almost always only an intermediary between the provider's communication center and the user device. Therefore, it is not uncommon for the points Wi-Fi access(the so-called hotspots) and even entire networks of such hotspots are interconnected by means of WiMAX technology.

Secondly, due to the sufficiently long range of transmitters (up to 50 km) and the very low sensitivity of the radio signal to various kinds of obstacles, WiMAX access points on the Internet can be created without reference to a geographic location (which, in fact, reflects the name WiMAX). All these factors allowed the creators of WiMAX to declare that their brainchild is suitable for the deployment of computational wireless networks of urban scale - Wireless Metropolitan Access Network (WMAN).

Types of WiMAX networks

Today there are several WiMAX specifications in the world:

  • Fixed WiMAX- fixed;
  • Nomadic WiMAX- providing session work: the user can connect to different base stations, but when moving between them he will be forced to disconnect from the WiMAX network;
  • Portable WiMAX- portable. The subscriber device can be in motion at a speed not exceeding 40 km / h;
  • Mobile WiMAX- mobile. It is possible to work on the move at a speed of up to 120 km / h.

The most popular are the first and last solutions.

The fixed type of access is intended for communication between two sufficiently remote objects, for example, two towers with WiMAX transmitters located at a distance of up to 50 km from each other. When you are in the line of sight and favorable conditions, the data transfer rate can reach up to 120 Mbit / s. Such impressive parameters allow using this mode as a replacement for traditional wired channels. This specification is referred to as 802.16-2004 or 802.16d. The frequency ranges of 3.5 and 5 GHz are allocated for the operation of WiMAX networks that comply with this specification.

Another type of access - mobile - allows the user to connect to the Internet any WiMAX-enabled device from anywhere. The signal goes directly to a modem, laptop, communicator or cell phone. At the same time, their owner, along with all his wireless "household" can move at speeds up to 120 km / h. Faster, however, is not recommended, otherwise the connection may disappear, since the base stations will not have time to transfer data without breaking the connection. It is these WiMAX networks that are being deployed today in Moscow, St. Petersburg and other large cities of Russia. This specification is referred to as 802.16-2005 or 802.16e.

WiMAX specifications strictly define the frequency ranges used, bandwidth, device radiation power, data transmission and access methods, signal coding and modulation methods, and other characteristics, and for each of them these parameters differ so much that WiMAX networks and devices of different specifications are incompatible. Detailed comparison technical characteristics WiMAX modes are listed in the table above.

In Russia, there are only mobile WiMAX networks. By the way, it is impossible to use the equipment of one WiMAX operator in the network of another in Russia.

How WiMAX works

Despite the fact that WiMAX is a radio technology, it will not be possible to completely do without wires even if you choose mobile mode... The principle of operation of a WiMAX-based network is very similar to the principle of operation cellular communication... There are subscriber stations, that is, base stations, user, etc. communication equipment operator connected to the Internet. Base stations are installed at a distance of several (or even tens) kilometers from each other. One "flips" the signal to the other in line of sight in the frequency range from 10 to 66 GHz (as already mentioned, the data transfer rate can be very high). At least one base station must be connected to the provider's network using wires. In practice, however, to wired network quite a few transmitters are connected, which improves the speed of data transmission and the reliability of the entire system.

Thus, the entire chain of base stations is connected at the operator end to the Internet via wires. At the other end of this line, no more than ten kilometers from the last base station, there may be a user's receiving antenna. It is installed outside the building or inside it; in addition, it can be connected directly to the device (again in the case of choosing the mobile mode). This antenna receives the signal from the last transmitter. In this case, more low frequencies: 1.5-11 GHz for fixed WiMAX and 2-6 GHz for mobile version... And the speed of data transmission from the base station to the subscriber device will be much lower. If you use a landline connection, then the maximum possible speed will be no more than 75 Mbit / s, and with mobile connection and even less - 30 Mbps. But even these figures are unattainable in practice. No wonder that prudent manufacturers WiMAX equipment Never forget to mention that the data rate depends on many factors: network load, urban density and even weather conditions.

One way or another, from the receiving antenna, the signal can go either directly to the user device, or via wires to the router.

Technological features of WiMAX

How can WiMAX successfully replace traditional types of broadband Internet access?

First, the new networks implement the principle of access priority sharing, the so-called "Quality of Service" (QoS). Without delving into the technological subtleties, we can say that in practice it looks like this: each subscriber receives a communication channel that is assigned only to him. At the same time, the transmission of information packets is carried out with a certain time delay (jitter). Thanks to such a separate scheme of work, the channel is not "clogged" and a stable connection is maintained. When the connected device leaves the range of a particular base station, its communication channel is transmitted next.

Secondly, to provide communication, the technology of orthogonal frequency multiplexing (OFDM), as well as its version for multiple access of subscribers (OFDMA), is used. Simply put, the communication channel is divided into many subchannels (up to 256) and the user receives not one channel, but several at once. The use of OFDMA makes it possible to increase their number to 2048 and connect eight subscribers to one line at once.

In addition, in WiMAX networks it is possible to apply several types of frequency modulation and change the bandwidth.

Various combinations of these criteria ultimately affect the traffic rate.

WiMAX coverage maps of Moscow

On the website of both Moscow WiMAX operators, there is a warning that the signal quality shown on the map may differ from the declared one. The published coverage maps (Fig. Above) reflect only the general situation, but do not take into account the specifics of the specific area where you will be working. So, before signing a contract, pay attention to the surrounding objects: buildings, power lines, newly built iron structures - all this can play a negative role when working on the network. However, if you live on the upper floors of an apartment building, then most likely there will be no problems with communication. The next step will be the acquisition of equipment. Today there are many devices that support WiMAX technology.

How do I connect to a WiMAX network?

First, you need to choose a WiMAX service provider. Finding them will not be difficult - just type the phrase "WiMAX provider" in an Internet search engine. Then you will need to familiarize yourself with the operator's coverage map. Despite the fact that we are talking about a wireless network on a city scale, WiMAX is not even available in all areas of the Russian capital.

WiMAX and competitors

Today wireless computer networks on the basis of WiMAX are rapidly developing both in Russia and abroad. However, no one undertakes to guarantee them a complete victory in 5–8 years. Why is that? The reason is that there are competing technologies for wireless broadband Internet access, which are supported and implemented by powerful market players - cellular operators.

What devices can work on WiMAX networks?

WiMAX-modems specially designed for this, as well as any computers and communicators equipped with a WiMAX-module or allowing to connect an external WiMAX-modem. On Russian market several types of WiMAX modems are presented.

  • USB modems- the easiest-to-use universal device, slightly larger than a regular flash drive (sold by both Comstar and Yota). USB modems are the most popular way to connect to WiMAX networks in Russia. Such devices cost about 2 thousand rubles, connect easily, do not require settings. You can purchase Nortel models (in case of a contract with Comstar) or Samsung (if you chose Yota).
  • ExpressCard Modems designed primarily for laptops. There are no problems with their installation and use (so far they are sold only by the Yota operator, with an adapter for PCMCIA connectors).
  • Laptops and netbooks with built-in adapters- so far, only Yota offers such devices, but in the near future, it is possible that similar offers will appear from Comstar.
  • Communicators and phones- Yota offers its customers to purchase working under Windows Mobile communicator HTC MAX 4G, specially "sharpened" for the network of this operator. No additional programs you do not need to install to access the Internet, but the user will no longer be able to connect to other providers. In Moscow, this device costs about 24 thousand rubles. A more affordable alternative is Nokia smartphone N810, which received a firmware last year to work with a WiMAX network, - about 13 thousand rubles.
  • Routers- allow you to connect more than one computer to the Wi MAX-channel, but several at once, and you can use special devices combining WiMAX and Wi-Fi technologies. As a rule, these are rather powerful machines (Yota WiMAX Wi-Fi Center or ASUS 500gP) costing about 10 thousand rubles. So far, they are sold only to corporate clients.

WiMAX security

The safety in the use of certain devices is of concern to many today. We are talking about both the possible harmful effects on human health and the safety of confidential data transmitted over the network and stored on a PC. Experts are in a hurry to assure that WiMAX is already clean here. The power of user WiMAX antennas is an order of magnitude less than that of cell phone... In addition, we hold the phone directly to the head, and the device for communication with the network at a distance. As for the security of data transmission, the 802.16e standard includes the use of triple encryption technology according to the DES 3 algorithm, in which the length of the cipher key is much longer than the standard one. Therefore, it will be much more difficult to crack the code. In addition to sophisticated encryption methods, WiMAX has a double certification level: both devices and manufacturers have their own certificates. As a result, it will be extremely difficult to intercept and use the data transmitted over the WiMAX channel.

What is required to connect to a WiMAX network?

As a rule, it is enough to buy a modem or laptop with WiMAX support, conclude a contract with the operator and deposit money into the account, and if you chose to connect via an external modem, then install the software that controls it. It is usually stored either in the modem's memory or on the supplied optical disc.

Such devices can be purchased either from the operators themselves, or in ordinary stores selling computer equipment. Today, both branded or certified by PC operators and models without certificates are presented on the market.

Note that not all Russian providers are ready to provide their services to users whose devices have the necessary chips, but are not officially recognized by the WiMAX operator. Moreover, even if you manage to download and install the control software and conclude a contract with the company, the operator will not guarantee that your device will work stably in the WiMAX network. The maximum possible speed on the network is not guaranteed either.

It is quite easy to install software from Yota and Comstar, as already noted, but the connection methods will be different. For example, Samsung USB modems have software already "wired" into internal memory modem. Therefore, it will only be necessary to connect it to the PC and, if the software installation did not start automatically, in the “My Computer” folder, click on the “Yota Access” icon, and then on “AutoInstall”, and wait until the program installs all the necessary files and appears network discovery message. To install Comstar's product, first load the supplied driver CD - they are not stored inside the Nortel modem, then run the Setup installer.

WiMAX is a wireless communication standard that provides broadband communication over long distances at speeds comparable to cable connections, that is, a synchronous channel of 256, 512, 2048 kbps and more. Building networks based on WiMAX technology allows providing broadband access to the Network in areas where cable networks are impractical for various reasons, as well as organizing communication between buildings and other objects located at a distance of 15-25 km.

There are two types of WiMAX: fixed and mobile

WiMAX systems based on different versions are not compatible. Brief characteristics each version is shown below.

802.16-2004 (also known as 802.16d and fixed WiMAX). Specification approved in 2004. Fixed access is supported in areas with or without line of sight. User devices include fixed outdoor and indoor modems and cards for laptops. In most countries, the 3.5 and 5 GHz bands are allocated for this technology. Many analysts see it as a complementary wired broadband technology.

802.16-2005 (also known as 802.16e and mobile WiMAX). Specification approved in 2005. Optimized to support mobile users, the version supports a number of specific features such as handover, idle mode and roaming. It can work with or without line of sight. The planned frequency ranges for Mobile WiMAX networks are as follows: 2.3-2.5; 2.5-2.7; 3.4-3.8 GHz. Several projects have been implemented in the world, including the first in Russia to deploy its network "Skartel". 802.16e competitors are all third generation mobile technologies (eg EV-DO, HSDPA).

The main difference between the two technologies is that fixed WiMAX allows serving only “static” subscribers, while mobile WiMAX is focused on working with users traveling at speeds up to 120 km / h. Mobility means the presence of roaming functions and "seamless" switching between base stations when the subscriber moves (as happens in cellular networks). In a particular case, mobile WiMAX can also be used to serve fixed users.

Mobile and fixed WiMAX networks in Russia are being built by:

* "Prestige-Internet" under the trademark "Enforta" (more than 80 large cities of Russia)

* "Skartel" under the trademark "Yota" (Moscow, St. Petersburg, Ufa, Krasnodar, Sochi, Samara, Kazan, Chelyabinsk)

* Comstar

* Synterra

* "NTK" (Vladivostok)

* "New telecommunications" under the trademarks "WiTe" and "NEX3"

* "Interproject" under the trademark "Freshtel" (Tula, Novomoskovsk, Chekhov, Serpukhov)

* Trivon Networks under the Virgin Connect trademark,

* CJSC MediaSeti under the UnitLine trademark

* Sovtest (Kursk)

* DARS TELECOM (Ulyanovsk)

* GLOBALFON (Ivanovo, Sochi, Kuznetsk)

* NewCom (Tyumen)

* as well as more than 20 regional Internet providers

Wireless technologies: Wi-Fi and WiMAX

By the end of the 2000s, many Russian users two popular wireless technologies: Wi-Fi and WiMAX. The first appeared a little earlier and is now more widespread, the second - a little later and develops mainly in large cities of Russia. Let's consider them in order, paying attention to the features of the application, pros and cons, similarities and differences. We will not consider the standards of existing mobile wireless networks - this is a topic for a separate article. But let's briefly talk about the prospects for the development of Wi-Fi and WiMAX.

Let's start with the advantages and disadvantages of wireless networks over traditional ones. The main plus, as the name suggests, is the lack of wires. This means that there is no need to lay cables, drill walls, install channels and ducts, etc. The network can be easily expanded, unlike wired ones, where the number of free ports in routers and hubs (hubs) serves as a limitation. The speed of connection of a new subscriber is also important. But what attracts people most about wireless networks is mobility. For example, at present, you can deploy a local network in an apartment or office within half an hour on Wi-Fi base and provide all devices with Internet access.

There are also disadvantages. First, there are problems with the stability of the connection. Standard home Wi-Fi routers have a range of several tens of meters indoors and up to 100-200 meters outdoors. However, some electronic devices(Microwave oven), various obstacles (reinforced concrete walls), as well as weather events (rain) weaken the signal strength of Wi-Fi and WiMAX networks. Thus, it will be difficult or even impossible to provide communication between subscribers located in neighboring buildings or on different floors. For Wi-Fi networks, you can buy a powerful transmitter, but devices with a power of more than 100 mW, according to Russian laws, cannot be used without registration with the relevant supervisory authorities. So we come to the second minus - the legal aspects of using frequency range and wireless transmitter / receiver settings that vary from country to country.

There is also a security issue, in particular Wi-Fi networks. The fact is that the popular WEP encryption standard is relatively easy to break, and the more advanced WPA and WPA2 protocols do not support many older access points. The fourth minus is the rather high power consumption of devices when using Wi-Fi and WiMAX networks. However, the pros generally outweigh the cons.

Wi-Fi (Wireless Fidelity) is a trademark for wireless networks based on the IEEE 802.11 family of standards. The protocol began in the Netherlands in 1991, when a firm introduced WaveLAN wireless checkout systems with data rates ranging from 1 to 2 Mbps.

Since then, IEEE 802.11 has evolved a lot. For example, the now popular IEEE 802.11n protocol standard, approved on September 11, 2009, allows data transmission at a theoretical speed of up to 600 Mbps with the simultaneous use of four antennas or 150 Mbps with one antenna. The real speed, of course, turns out to be two to three times less. In this case, you can use one of two operating frequency ranges - 2.4 or 5 GHz. In addition, for 802.11n, the developers have retained backward compatibility with the legacy 802.11a and 802.11b / g standards.


Works Wi-Fi network in the following way. The first step is to install a Wi-Fi transmitter or, in other words, an access point (hotspot), to which anyone in an accessible way Internet connection (cable, satellite, WiMAX, Mobile Internet). Further, the access point itself becomes a source of distribution of the Internet to client devices: computers, laptops, netbooks, smartphones and other mobile devices. The only thing is that they should all have a built-in or external W-Fi adapter (receiver).

Wi-Fi receivers have long been built into laptops and many mobile devices. For stationary PCs or outdated laptop models, you will have to buy a special module. It can be a card for PCI slots, MiniPCI, PCMCIA, or a USB adapter. There are also miniature receivers the size of an SD memory card. These Wi-Fi adapters cost only a few hundred rubles. Modules can be embedded in other devices such as media players. The cost of Wi-Fi transmitters (routers) starts from one thousand rubles, some Internet providers provide such equipment for free.

The Internet in Wi-Fi networks is shared among all subscribers, therefore, with a large number of connected devices, the data transfer rate will be reduced. The networks themselves are subdivided into public and private. The former are created in public places (train stations, hotels, cafes, parks, etc.) and usually do not require identification for connection. In a number of foreign cities, public wireless Wi-Fi networks are combined into common ones and they cover almost the entire urban area.

Private networks are used for personal or corporate purposes by a limited group of people and are protected by a password or key. However, due to the inexperience of network administrators who forget to set a password, anyone can connect to them. There are even underground maps of such points, thanks to which it is not difficult to find free Internet in large cities.

IEEE 802.11ac and IEEE 802.11ad standards are currently being developed. The first technology allows to distribute the Internet in parallel streams to more than three users at a speed of several gigabits per second to each in the 5 GHz range, the second - to one subscriber up to 7 Gbps in the 60 GHz range, which limits the coverage area to the scale of one room.

In addition, the IEEE 802.22 WRAN standard is being developed. The so-called Super Wi-Fi promises speeds of up to 22 Mbps within a radius of up to 100 km from the nearest transmitter. In this case, the data will be transmitted on unoccupied television broadcast frequencies (VHF / UHF). In the future, the 802.22 standard should provide the Internet for sparsely populated areas and developing countries.

In addition to Wi-Fi, there is another wireless communication standard - WiMAX, which is developing at an equally fast pace, but in many respects differs from it.

WiMAX (Worldwide Interoperability for Microwave Access) is based on the IEEE 802.16 standard. A network based on this technology is built from base and subscriber stations and equipment that connects base stations with an Internet provider and other services. The used frequency range is from 1.5 to 13.6 GHz. The range is 6-10 km for "static" subscribers and 1-5 km for "mobile" subscribers moving at speeds up to 120 km / h. The data transfer rate can reach 40-75 Mbps. WiMAX was created as a universal wireless connection for a wide range of devices (from PCs and laptops to mobile phones and tablets) operating over long distances.

It should be noted right away that under the name WiMAX two standards are combined - 802.16d (fixed WiMAX) and 802.16e (mobile WiMAX), the developers have not managed to combine them. Each specification has its own operating frequency ranges, bandwidth, radiation power, transmission and access methods, signal coding and modulation methods, and other characteristics. Therefore, WiMAX systems based on different versions of the IEEE 802.16 standard are practically incompatible.

The 802.16d standard (aka 802.16-2004) uses stationary modems and PCMCIA cards for laptops. Communication is possible only with fixed subscribers. In this case, the following characteristics can be achieved: speed up to 75 Mbit / s, communication range - 25-80 km, used frequency range - 1.5-11 GHz (more often 3.5 and 5 GHz are used).

The 802.16e standard (802.16-2005) is optimized for use with mobile users. The characteristics are as follows: speed up to 40 Mbit / s, communication range - 1-5 km, used frequency range - 2.3-13.6 GHz (more often - 2.3-2.5; 2.5-2.7; 3 , 4-3.8 GHz). 802.16e is also used to serve fixed users. It is he who is most often offered to users by various providers.

Thus, mobile WiMAX is a competitor to modern mobile technologies and fixed WiMAX to wired broadband DSL. End users wishing to connect to WiMAX networks must first select a provider and conclude an agreement. They will then receive a USB modem, ExpressCard modem, or similar device. You can buy a WiMAX receiver yourself, in addition, a number of mobile devices and laptops already have built-in support for WiMAX technology.

In the future, the two specifications should be replaced by a single 802.16m standard (WiMAX 2). It will be more productive, faster (speed up to 100 Mbps for the mobile version and up to 1 Gbps for the fixed version). There will also be support for the latest communication technologies.

Finally, let's look at the qualitative differences between Wi-Fi and WiMAX. Wi-Fi is a short-range system (tens of meters), with its help it is convenient to create local area networks not necessarily connected to the Internet. WiMAX is a long-range (kilometers) system that connects the provider and the end user. Home network it is more difficult to build on its basis, but a network covering large areas is easier. When comparing, this analogy is often used: WiMAX is compared with mobile communication, and Wi-Fi - with a landline wireless telephone.

If you are an avid proponent of wireless networking, for you the best option will following diagram(see the figure above): use WiMAX as a backbone channel from the provider, and then distribute the Internet between consumers based on a local Wi-Fi network.

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