Wireless data transmission technologies. Wireless networks for IoT and M2M. Basic data transmission mechanisms

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Wireless data transmission systems

Introduction

Currently, wireless data transmission systems are widely used in most spheres of society.

They owe this attention to:

Low cost

Mobility

Independence from cable infrastructure

High-speed Internet access

Easy to connect and use

The development of wireless access systems goes in three main directions:

1. Satellite systems

2. Systems of personal cellular communication

3. Ground microwave systems

Each of these tools has advantages and disadvantages. Wireless networks are most effective when transmitting data over distances of several hundred meters.

1. Evolution of wireless networks

More recently, mobile phones were really phones, not smartphones as they are now. These "ancient" phones could support a minimal set of functions, for example, make only calls and send text messages. It is good that those days are behind us and the promising new generation wireless high-speed data networks are actively developing around the world, and some things are starting to seem confusing. Let's note for a start that the prefix "G" stands for "generation" (from the English. Generation).

1.1 1G

The story begins with the emergence of several network technologies in the 1980s: a combination of NMT and TACS in Europe and AMPS in the USA. The trio of NMT, TACS and AMPS are considered the first generation of 1G wireless network because it was these technologies that allowed mobile phones, as we see them now, to become a mass product. In those days, no one thought of a data transmission service, since these were purely analog systems, invented and designed exclusively for voice calls and some other modest capabilities. Data transfer rates were also slow and expensive.

1.2 2G

The early 1990s saw the rise of the first digital cellular networks, which had higher sound quality, increased performance, greater security, etc. GSM began its development in Europe.

The second generation of the 2G wireless network already had support for short text messages (SMS), as well as data transmission technology (CSD - a data transmission technology developed for GSM mobile phones), which allowed data to be transmitted in digital form. All this made it possible to increase the data transfer rate up to 14.4 kbps.

1.3 2.5G

In 1997, the GPRS service appeared. Its appearance was a watershed moment in the history of wireless cellular communications, because with its appearance, existing GSM networks began to support continuous data transmission. With GPRS, you can only transfer data when needed. The GPRS speed was higher than the CSD speed and theoretically reached 171.2 kbps, and the operators were able to charge not for the time on the line, but for the traffic.

The surge in popularity of GPRS in such a short time is explained by the fact that people began to actively check their mailboxes. When GPRS technology was already on the market, the International Telecommunication Union (ITU) published a new standard - IMT-2000, which approves the 3G specifications. The main thing in this story is that 3G devices must provide data transfer rates up to 2 Mbps for stationary terminals and 384 kbps for wireless networks, which was beyond the power of GPRS. So GPRS was stuck between generations, 2G - which it outperformed, and 3G - which it fell short.

1.4 3G, 3.5G, 3.75G

In 2003, the EDGE standard was first introduced in North America. This standard allowed GSM network operators to squeeze additional juice out of 2.5G networks without investing a lot of money in equipment upgrades. With the help of a mobile phone supporting EDGE, subscribers could get twice the speed of GPRS, which was quite good for that time.

In 2004, GSM carriers in North America supported EDGE. This was due to the emergence of a strong rival CDMA2000. It provides data transfer rates slightly faster than GPRS. Most of the other GSM operators considered UMTS technology as the next step in their development, so they chose to either skip the introduction of EDGE. However, as practice has shown, the high cost and volume of work on the implementation of UMTS forced some European operators to reconsider their views on EDGE as expedient.

Some time later, CDMA2000 wireless networks received the 1x EV-DO Rel.0 update. The update increased the incoming speed to 2.4 Mbps and the outgoing speed to 153 kbps. Thus, we got 3.5G.

The transitional generation 3.5G is represented by the HSDPA standard.

For cellular networks today, there are several protocols that increase data transfer rates. However, in fact, none of them are able to save mobile network resources, which makes such traffic expensive and inefficient. The HSDPA protocol, conceived by leading manufacturers of mobile infrastructure equipment, is designed to increase network performance precisely through more efficient use of the radio channel, in particular, by reducing packet transmission delays. HSDPA technology is not new, but it changes the user's perception of third generation mobile data networks.

HSDPA (English High-Speed \u200b\u200bDownlink Packet Access - high-speed packet data transmission from a base station to a mobile phone) is a mobile communication standard considered by experts as one of the transition stages of migration to fourth-generation mobile communication technologies (4G). The maximum theoretical data transfer rate according to the standard is 14.4 Mbit / s, the practical achievable in existing networks is about 3 Mbit / s.

1.5 4G

Like 3G, the ITU took control of 4G, tying it to the IMT-Advanced specification. The specification sets the speed of incoming data at 1 Gbps for fixed terminals and 100 Mbps for mobile devices. These are truly tremendous speeds that even a direct broadband connection can overtake.

No commercial standard meets these specifications, but it just so happens that WiMAX and LTE are considered 4G technologies, but this is only partly true, as they both use new, extremely efficient multiplexing schemes, and both lack a channel for voice transmission ... We can confidently assert that 100% of their bandwidth is used for data services.

As practice has shown, WiMAX and LTE have failed in data transfer rates. Theoretically, the speed values \u200b\u200bare at the level of 40 Mbit / s and 100 Mbit / s, and in practice, the real speeds of commercial networks do not exceed 4 Mbit / s and 30 Mbit / s, respectively. This fact does not meet the high requirements of IMT-Advanced. Only upgrades to WiMAX Release 2 and LTE-Advanced were able to achieve these speeds.

1.6 5G

Not all major cities have deployed fourth-generation LTE networks yet, and telecommunications companies are already making plans for fifth-generation (5G) services. For example, Japan's NTT DoCoMo believes that the launch of such networks will become possible in 2020: compared to LTE, they will provide a hundredfold increase in data transfer speed and a thousandfold increase in throughput.

Researchers from Chalmers University of Technology (Sweden) described what infrastructure changes may be required when introducing 5G technologies.

Let's start with some statistics. In 2012, the number of cellular subscribers who own smartphones was 1.2 billion. By 2018, their number is projected to grow to 4.5 billion. Mobile traffic has doubled between the first quarters of 2012 and 2013, and by the end of 2018 it will jump another 12 times.

It is clear that the increase in the number of mobile devices with a web connection will lead to a sharp increase in the load on data transmission channels and generate the need for an increase in speed. 5G networks should be the solution to the problem.

Researchers identify five main directions in the scenario of the next generation communication systems development. This is a multiple increase in speed compared to 4G / LTE, the ability to provide high-quality services even in the most densely populated areas, maintaining a stable connection with a large number of devices with a web connection (we are talking about the "Internet of Things"), high quality services for end users and minimal delays.

At the beginning of the year, the European Commission allocated € 50 million for research related to fifth generation mobile communications. Grants are awarded to scientific organizations and scientists working in communication technologies. For example, the participants of the METIS (Mobile and wireless communications Enablers for the Twenty-twenty Information Society) project, in which the Chalmers University of Technology is involved, received € 16 million.

METIS has already defined the basic requirements that 5G networks must meet:

1. Increase in the data transfer rate by 10-100 times per subscriber - up to 1-10 Gbps.

2. Growth of consumed traffic by 1000 times - up to 500 GB per user per month.

3. Increase in the number of connected devices by 10-100 times.

4. Tenfold increase in battery life of devices with low power consumption, such as sensors.

5. Reducing the response time of systems to 5 ms or less.

6. Maintaining the same operating and energy costs.

One of the proposed solutions to these problems is called the installation of small, low-power base stations in homes, on street lamps, and even on cars and public transport. This will shorten the distance between the information transmitter and the end user and, therefore, increase the efficiency of the main base stations and increase the data transfer rate.

In addition, compaction of the base station infrastructure will reduce the radiation intensity and improve the energy efficiency of all devices without exception by reducing the signal power.

Essentially, the researchers say, fifth-generation networks will create the foundation for an intelligent community in which people and devices can share data anywhere, anytime.

2. Classification of wireless technologies

There are different ways to classify wireless technologies

2.1 By range

Figure 1 - classification of wireless technologies by range

Personal wireless networks

Wireless personal area networks (WPAN) -networks used to communicate various devices. The range of WPAN can be up to several meters.

Wireless local area networks (WLAN)

In such a network, data transmission is carried out over the air. The most common representatives of such a network are Wi-Fi and WiMAX.

Wireless Wide Area Networks (WWAN)

WWAN differs from WLAN in that it uses cellular technologies such as GSP and GPRS.

City Scale Networks (WMAN)

Such networks provide broadband access to the network through a radio channel.

By topology

Point-to-point networks

A point-to-point network is the simplest type of computer network in which two computers communicate through communication equipment.

Point-to-multipoint networks

Such networks are used to connect three or more objects.

2.2 By scope

2.2.1 Corporate networks

The corporate data transmission network is a system that provides information transfer between various objects that are used in the corporation's system. They are created by companies for their own needs.

2.2.2 Operator networks

Operator networks are networks that are created by telecom operators for the provision of paid services.

3. The most common wireless data networks

3.1 Bluetooth

The most prominent example of a wireless personal area network is Bluetooth. It enables data transfer between personal devices such as laptops, smartphones, tablets, etc.

Bluetooth is a WPAN specification. Being a wireless personal area network, Bluetooth connects personal devices (laptops, mobile phones, mice, headphones, GPS adapters, etc.) into one whole. Operates in the 2.4 GHz frequency range, depending on the network class, the distance can be from one to one hundred meters.

Bloetooth versions:

Bluetooth 1.0, 1.1, 1.2, 2.0, 2.1. These specifications are outdated and do not fit into new devices. Other, more modern options are of interest.

Bluetooth 2.1 + EDR (Enhanced Data Rate). Data transfer rates up to 2.1 Mbit / s.

Bluetooth 3.0 + HS (High Speed). Includes two subsystems - for high speed (theoretical maximum 24 Mbit / s) and for low power consumption (up to 3 Mbit / s). Switching occurs automatically depending on the needs.

· Bluetooth 4.0. Added Bluetooth low energy specification. Designed for small sensors (for example, in shoes, exercise equipment), the battery life of such sensors can reach several years. Peak transfer rate up to 1 Mbps.

Different devices can support all sorts of protocol extensions called profiles. The user is most interested in the following profiles:

A2DP (Advanced Audio Distribution Profile). Designed to transmit stereo sound (for example to headphones). There is a version for both receiver and transmitter. A2DP devices can support all kinds of codecs like MP3, AAC, etc.

File Transfer Profile (FTP_profile). File transfer, directory listing.

HID (Human Interface Device Profile). Support for input devices - mice, keyboards, joysticks. Requires less energy.

3.1.1 Principle of operation

Operating principleBluetooth is based on the use of radio waves. Bluetooth radio communication is carried out in the 2.4-2.4835 GHz band (ISM band). Bluetooth uses Frequency Hopping Spread Spectrum (FHSS).

According to the FHSS algorithm, in Bluetooth, the signal carrier frequency hops 1600 times per second. The sequence of switching between frequencies is known only to the transmitter and receiver, which synchronously re-tune from one carrier frequency to another every 625 microseconds. Thus, if several pairs of receiver-transmitter work nearby, then they do not interfere with each other. This algorithm is also an integral part of the system for protecting the confidentiality of transmitted information: the transition occurs according to a pseudo-random algorithm and is determined separately for each connection.

Bluetooth protocol supports not only point-to-point connection, but also point-to-multipoint

3.1.2 Benefits

Bluetooth does not require line of sight between devices to sync. This means that the devices do not have to face each other, and it is also possible to transmit when both devices are in separate rooms. The fact that this technology does not require wires or cables has made it so popular. The maximum range for Bluetooth transmission is 100 meters, but this range is not the same for all Bluetooth connections. It depends on the characteristics of the device and its version.

One of the main advantages of Bluetooth is its ease of use. Anyone can understand how to set up the connection and synchronization of two devices. Moreover, the technology is completely free to use. Bluetooth 2.0 introduces support for multi-cast, which means sending data to multiple devices at the same time. The chance of interference from other wireless networks on the Bluetooth network is very low. This is due to the low power of wireless signals and frequency hopping. Bluetooth works in the same frequency range as Wi-Fi 2.4 GHz. In some very rare cases, connections can conflict with each other.

3.1.3 Disadvantages

The main disadvantage Bluetooth is low security. There are now many hacker spyware programs that allow you to get into your device if it has Bluetooth enabled. Battery wear is not significant during one Bluetooth transmission, but there are some people who leave Bluetooth enabled in their devices. This is inevitable, dramatically reducing battery life.

3.2 Wi-Fi

Wi-Fi - wireless networks based on the IEEE 802.11 standard.

Figure 3 - Wi-Fi logo

Wi-Fi standards:

1. IEEE 802.11b - Describes faster transmission rates and introduces more technology constraints. This standard was widely promoted by the WECA (Wireless Ethernet Compatibility Alliance) and was originally called Wi-Fi. Frequency channels are used in the 2.4GHz spectrum. Ratified 1999. RF technology used: DSSS. Maximum data transfer rates in the channel: 1, 2, 5.5, 11 Mbps

2. IEEE 802.11a - describes significantly higher transmission rates than 11b. Frequency channels in the 5GHz spectrum are used. RF technology used: OFDM Protocol Not compatible with 802.11b. Ratified 1999. Maximum data transfer rates in the channel: 6, 9, 12, 18, 24, 36, 48, 54 Mbps.

3. IEEE 802.11g - describes data rates equivalent to 11a. Frequency channels are used in the 2.4GHz spectrum. The protocol is compatible with 11b. Ratified in 2003. RF technologies used: DSSS and OFDM. Maximum data transfer rates in the channel: 1, 2, 5.5, 11 Mbps for DSSS and 6, 9, 12, 18, 24, 36, 48, 54 Mbps for OFDM.

4. IEEE 802.11n is the most advanced commercial Wi-Fi standard at the moment. Frequency channels in 2.4GHz and 5GHz spectra are used. Compatible with 11b / 11a / 11g. Although it is recommended to build networks with an 11n orientation only, since it is necessary to configure special protection modes if backward compatibility with legacy standards is required. This leads to a large increase in signaling information and a significant decrease in the available useful performance of the radio interface. Actually, even one 11g or 11b client will require special tuning of the entire network and its immediate significant degradation in terms of aggregated performance. The 802.11n standard itself was released on September 11, 2009. Frequency channels 20MHz and 40MHz (2x20MHz) are supported. RF technology used: OFDM.

3.2.1 How Wi-Fi works

Typically, a Wi-Fi network scheme contains at least one client and one access point. Also, in point-to-point mode, when an access point is not used, and clients are directly connected by network adapters, it is possible to connect two clients. At a rate of 0.1 Mbps, the access point transmits its network identifier using special signal packets every 100 milliseconds. Therefore, 0.1 Mbps is the lowest data transfer rate for Wi-Fi. Knowing the network identifier, the client can find out if it is possible to connect to this access point. When two access points with identical network identifiers fall within the coverage area, the receiver can choose between them based on the signal strength data.

3.2.2 Benefits

Possibility deploy a network without laying a cable, which reduces the cost of deploying and expanding the network. Wireless networks serve places where cable cannot be laid

Allows mobile devices to access the network.

Widespread in the market. Guaranteed equipment compatibility due to the mandatory certification of this brand of equipment.

Mobility.

In the Wi-Fi zone, several users can access the Internet from portable devices and computers.

The radiation from devices using Wi-Fi at the time of data transfer is 10 times less than the radiation from a cell phone.

3.2.3 Disadvantages

In the range 2.4GHz operates many devices that support other types of wireless networks that degrade electromagnetic compatibility.

The WEP encryption standard can be cracked relatively easily even with the correct configuration (due to the weakness of the algorithm). There is WPA (2) encryption, but in point-to-point mode, the standard prescribes only 11 Mbps (802.11b). WPA (2) encryption is not available, only easy-to-break WEP.

3.3 WiMAX

Telecommunication technology based on the IEEE 802.16 standard, also called Wireless MAN.

3.3.1 Operating principle

WiMAX networks consist of several parts - base and subscriber stations, as well as equipment that connects base stations.

Base stations and subscriber stations communicate using radio waves in the 1.5-11 GHz range. Data exchange can take place at a speed of 70 Mbps.

Base stations communicate with line-of-sight connections at a frequency of 10-66 GHz, and the data exchange rate reaches 120 Mbps.

3.3.2 Benefits

WiMAX technologies will help to organize wireless access throughout settlements, helping to solve the "last mile" problem, as well as reducing financial costs for new connections. If now the connection of one object can last up to several months, then with solutions based on WiMAX this process will be reduced to several hours or days. Savings on the organization, laying and operation of structured cable networks (SCS), as well as the speed of installation and connection of equipment will significantly reduce investments in telecom infrastructure. WiMAX technologies provide not only voice transmission, but also any data, including video conferencing, Internet access, corporate networks and databases. The problem in using the WiMAX technology is the rather low security of information transmitted over radio channels. Now this issue is being solved by the manufacturers of the corresponding equipment. Nevertheless, WiMAX technology can be widely used when organizing corporate data transmission networks.

3.3.3 Disadvantages

Weather conditions and other wireless systems can interfere with the normal functioning of the radio access, completely different frequency ranges can be used for operation, the data transfer rate drops rapidly with increasing distance between the base station and the client equipment, the equipment is demanding on power supply and consumes quite a lot of power.

3.4 GPRS

3.4.1 How it works

UsingGPRS information is collected in packets and transmitted via voice channels that are not used at the moment. The transmission priority (voice or data traffic) is chosen by the service provider.

3.4.2 Advantages and disadvantages

The advantages of GPRS are the ability to connect to the Internet from anywhere in the world where there is a cellular connection, high speed data transfer, which allows you to quickly establish connections with the Internet and work with comfort, compactness and mobility.

The disadvantages of GPRS are the excessively high cost of one MB of information and the lowest access speed.

Conclusion

wireless network communication

Currently, wireless data transmission systems are an integral part of every person's life. Wireless networks are improving every year faster and faster, the technical characteristics of systems are improving significantly.

Improvements in wireless transmission systems could spur the development of technologies such as cloud storage. If the data transfer rate is very high, the need for hard drives may disappear.

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Oleg Ivanin for website

Wireless technologies are experiencing a true boom today. This is mainly due to the solid entry into our life of smartphones, tablets and mobile computers, which, among other things, can serve as universal dispatching consoles for an automated process control system, provided there is constant access to the Internet, regardless of whether the terminal moves in space. In addition, in various industries, agriculture, and the military sphere, there is a growing need to organize reliable control systems for distributed objects and integrate them into a global network. Similar trends are observed all over the world and lead to the inevitable development of wireless communication technologies.

APCS systems, which are often distributed, are currently characterized by a trend of modernization, provided that the main means of production (lines, machines and mechanisms) remain unchanged. The quality of production changes in a short time due to the modernization of the APCS, including the use of wireless technologies, which bring savings in time and money, compared to the deployment of wired networks.

This article examines and, in part, compares various products from manufacturers of wireless communications hardware, covering applications such as industrial process control systems and building management systems (BMS).

The types of wireless networks that are applicable in these areas are as follows:

Personal wireless networks.
Wireless sensor networks.
Small local wireless networks.
Large local wireless networks.

In our review, we do not consider equipment and software for organizing global networks and networks using the services of telecommunication providers (GSM, GPRS, EDGE, 3G, WiMAX, etc.)

Choice of technology for different systems

First, we will briefly dwell on the principles of choosing wireless hardware for organizing an ICS.

Today, the main problem for a wireless user is choosing the right technology. There are many types of wireless communications and, like wired networks, different systems have different requirements.

The choice of technology should be guided by the following factors:

Data volume: Some consumers need to collect megabits of data per second, while others only need to turn on and off individual devices a few times a day.
Response time: when the device is part of a chain, receiving the command at a given moment is essential. The required response time can be several microseconds.
Reliability of response: will the message be received with certainty and, if not, what is the probability of finding errors? Interference plays an important role here when choosing a technology.
Communication distance: are network nodes located over a large area or concentrated in one place? The distance can be from several meters for the moving parts of the machine to several kilometers for the pumping stations of the distribution network. The distance covered defines the power consumption and often determines whether a license-free communication technology can be used.
Number of sites: Whether communication is required between only two sites, or multiple sites are involved, requiring a more sophisticated communication structure (Scatternet topology).

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A quick tour of the types of wireless networks

Personal wireless networks

IrDA (Infrared Data Association) - communication in the infrared range of light waves
Bluetooth is a short-range radio technology (typically up to 200 meters) in a license-free frequency band (ISM band: 2.4-2.4835 GHz).
UWB (Ultra-Wide Band) is a short-range wireless communication technology (about 10 meters) that uses the widest frequency range for commercial communication devices.
Wireless USB, wireless USB - designed to replace wired USB.
Wireless HD is a wireless data transmission technology primarily intended for transmission of HD video, but it can also be used for wireless networking.
WiGig (IEEE 802.11ad.) Is a broadband wireless technology that operates in the 60 GHz unlicensed frequency band and provides data transmission up to 7 Gbps over distances up to 10 meters.
WHDi, Wireless Home Digital Interface (Amimon) is a wireless data transmission technology used for high speed data transmission and optimized for high definition video transmission.
LibertyLink is a wireless personal area network technology developed by Aura. The effect of magnetic induction is used to transmit information.
DECT / GAP - digital advanced wireless telephony system; wireless communication technology used in modern radiotelephones.

Wireless sensor networks

DASH7 is a wireless sensor networking standard. The sensor network is a network of miniature computing devices equipped with sensor sensors.
Z-Wave is a wireless radio technology used to organize sensor networks. The main purpose of Z-Wave networks is to remotely control household appliances and various household devices that provide control of lighting, heating and other devices for automating the control of residential buildings and office premises.
Insteon is a combined (partly wired and partly wireless) sensor network. To transmit information, a radio signal is used at a frequency of 902-924 MHz, which provides data transmission at a distance of up to 45 meters in line-of-sight conditions with an average speed of 180 bit / s.
EnOcean is a wireless sensor networking technology using ultra-miniature sensors with power generators, microcontrollers, and transceivers.
ISA100.11a is a standard for organizing industrial sensor networks, sensor networks and actuators. Low-speed wireless communication using low-power elements is used for transmission. A distinctive feature of ISA100.11a from other sensor networks: 1) focus on industrial use and, accordingly, specific requirements for strength, noise immunity, reliability and safety, 2) the ability to emulate protocols of existing and proven wired and wireless sensor networks using ISA100.11a technology ... Data exchange is carried out at a frequency in the 2.4 GHz region and a speed of about 250 kbit / s.
WirelessHART is a wireless communication protocol developed by the HART Communication Foundation for transmitting data in the form of HART messages in a wireless environment. HART is a communication protocol for communicating with field sensors.
MiWi is a protocol for the organization of sensor and personal networks with low data transfer rates over short distances, based on the IEEE802.15.4 specification for wireless personal networks.
6LoWPAN is a standard that allows small wireless networks (private networks or sensor networks) to interact with IP networks using the IPv6 protocol.
One-Net is an open protocol for wireless sensor networks and building automation networks and distributed objects.
Wavenis is a wireless data transmission technology using 433/868/915 MHz frequencies and providing transmission over distances of up to 1000 m in open space and up to 200 m indoors, at speeds up to 100 Kbps. Wavenis technology is used to organize personal networks and sensor networks, since the ultra-low consumption of transceiver devices allows them to work autonomously for up to 15 years from one battery.
RuBee is a local wireless network that is mainly used as a sensor network. RuBee uses magnetic waves to transmit data and transmit at 131 kHz, which provides a speed of only 1200 bps per second at distances from 1 to 30 meters.

Small local wireless networks

HiperLAN (High Performance Radio LAN) is a wireless communication standard. There are two revisions of the standard: HiperLAN 1 and HiperLAN 2. The HiperLAN 1 standard was released in 1981 and describes a slower communication line, providing data transfer rates up to 10 Mbps at distances of up to 50 meters.
Wi-Fi is a trademark of the Wi-Fi Alliance, a family of standards for the IEEE 802.11 specification for broadband radio communications. Depending on the standard, Wi-Fi uses a frequency range of 2.4 GHz or 5 GHz for data transmission and provides data transfer rates from 2 Mbps at distances up to 200 meters.
ZigBee is a technology for organizing wireless sensor and personal networks. ZigBee technology provides low power consumption and data transmission on an unlicensed 2.4 GHz frequency (for different countries the frequency may differ) at speeds up to 250 Kb / s, at a distance of up to 75 meters in line of sight.
RONJA (Reasonable Optical Near Joint Access) is a wireless data transmission technology using an optical signal.

Large local wireless networks

WiMAX (Worldwide Interoperability for Microwave Access) is a wireless data transmission technology based on the IEEE 802.16 standard. The main purpose of the technology is high-speed communication over long distances and the provision of Internet access.
HiperMAN is a wireless data transmission technology based on the IEEE 802.16 standard. European alternative to WiMAX technology. HiperMAN is specialized for packet data transmission and organization of wireless IP networks.
WiBro (Wireless Broadband) is a high-speed, long-distance wireless technology based on the IEEE 802.16e standard. North Korean analogue of WiMAX Mobile technology.
Classic WaveLAN is a wireless LAN technology (wireless alternative to wired Ethernet and Token Ring). Data transmission is carried out in the frequency range of 900 MHz or 2.4 GHz, while the transmission speed is up to 2 Mbit / s.

Manufacturers of hardware for organizing wireless networks of industrial control systems

This review will consider some interesting proposals of currently popular manufacturers presenting on the market equipment for:

Industrial control systems: Phoenix Contact, Siemens, Omron, Moxa
ACS of engineering systems of buildings and structures, "smart home": Thermokon, JUNG

In writing this review, the practical experience of using a number of the listed devices was widely used.

Phoenix Contact

With its sophisticated product range and excellent product functionality, Phoenix Contact has an excellent position in the market for wireless solutions for industrial automation.

Phoenix Contact supplies components for all wireless communication requirements in industrial environments. Wireless communication devices are designed for use in harsh industrial environments, are characterized by high reliability, simplicity and ease of use, as well as maximum data transmission security.

Transmitting a small amount of signals or huge amounts of data, providing real-time communication between devices located close or hundreds of meters away, in industrial premises with metal barriers or in open areas - for these and other requirements, it is possible to select the appropriate components and accessories. from Phoenix Contact.

Each application area has its own requirements for radio communications. Phoenix Contact offers a series of wireless communication products based on various technologies that enable you to solve communication problems flexibly, simply and economically.

Each specific field of application has its own functional and technical requirements for wireless communication technologies. Since none of the existing radio technologies can currently meet all requirements, Phoenix Contact offers solutions based on different technologies.

So, what kind of communication hardware does Phoenix Contact offer to customers?

Bluetooth I / O (IEEE 802.15.1). The main area of \u200b\u200bapplication of Bluetooth technology is the integration of automation system components into local area networks based on a fieldbus or industrial Ethernet. With support for a variety of user profiles, the wireless standard can be applied to a wide range of applications. Distinctive features:

A very reliable way of transmitting data in industrial premises with metal objects.
Possibility of local parallel operation of several Bluetooth networks.
Automatic coexistence mechanisms ensure anti-jamming parallel operation of WLAN 802.11b / g.
Radio network connection of up to seven terminal devices.
Bandwidth up to 1 Mbps.
The transmission range is generally over 100 m in industrial premises and over 200 m in open areas.
Ideal for fast cyclic transmission of small data packets.
Transparent data transmission over Ethernet at the Layer-2 level, for example in PROFINET IO systems.
High data security with 128-bit encryption and Trusted Wireless endpoint authentication.

Bluetooth I / O is an effective technology from Phoenix Contact for the automation of industrial workshops (for example, the textile, chemical industry) without creating an APCS project in relation to building structures. Project creation and system deployment can be done very quickly and there will be no additional cabling and hardware requirements.

Phoenix Contact Factory Line Bluetooth for wireless control signal transmission

Among the methods of reliable wireless data transmission, it is worth noting:

Trusted Wireless - industrial radio communication technology for the transmission of process signals that are not critical to delays over long distances - up to several kilometers.

Phoenix Contact Radioline based on Trusted Wireless technology

Wireless MUX - a simple solution for the transmission of digital and analog process and control signals - simple and reliable without a cable, from one point to another. Confident and reliable transmission over distances of up to several hundred meters.

Phoenix Contact Wireless-MUX multi-channel wireless communication system

Wireless I / O -technology for wireless transmission of process and control signals critical to delays in networks of automatic control systems. It is characterized by high performance, reliability, simple and convenient maintenance.

High-performance networks are represented by WLAN technology (IEEE 802.11). On the basis of WLAN, it is possible to implement networks that unite many terminal devices. Since WLAN systems can be easily integrated into information networks, they are ideal for mobile control, monitoring and data logging. In addition, it is possible to create a fast communication channel between control devices and transfer input and output data in real time in PROFINET I / O systems. Other features:

The ability to create large networks that unite several hundred terminal devices
High bandwidth up to 300Mbps.
Thanks to the automatic roaming function, it is possible to create networks with a large coverage area, ensuring high mobility.
The transmission range is typically up to 100 m in industrial premises and over 200 m in open areas. In some cases, the transmission distance can be more than 1 km.

The main types of Phoenix Contact equipment that support the listed technologies:

Wireless Ethernet -are used for wireless connection of automation system components to the Ethernet network. Data transfer at the Layer-2 level is carried out in a transparent mode with respect to protocols. Industrial Ethernet protocols such as PROFINET, Modbus / TCP and EtherNet / IP are supported.

Factory Line Bluetooth - Reliable communication components for small wireless LANs operating in parallel.

Factory Line WLAN -components that provide high-speed wireless Ethernet access with a large coverage area.

Factory Line Wireless Serial -serial devices that can be integrated into an Ethernet network using Factory Line Bluetooth or Factory Line WLAN components.

Reliability

Much attention is paid to the reliability and noise immunity of wireless communication channels in harsh industrial environments. Wireless data transmission is carried out by means of electromagnetic waves. In this case, external sources of electromagnetic interference affect the radio communication channel.

Strong electromagnetic fields of radio interference generated in industrial premises by various devices, for example, frequency converters, as a result of switching loads or operating a welding machine, do not affect radio communications, since such electromagnetic interference is within the kilo- or megahertz range, while Bluetooth, Trusted Wireless and WLAN operate in the 2.4 GHz band. Additionally, Bluetooth, Trusted Wireless and WLAN support spread spectrum signals and other mechanisms to ensure high reliability of data transmission.

Advantages

Of course, the advantages of this manufacturer include the reliability of ensuring the stability and noise immunity of communication channels due to modern methods of coding and organization of the radio channel. I would like to mention the Wireless MUX facilities (such as ILB BT ADIO MUX-OMNI) , which allow you to quickly deploy, for example, information and measurement systems and monitoring systems, up to the creation of diagnostic, mobile complexes for temporary use. Effective automation of mobile objects of the APCS can be carried out using the Wireless LAN access point, FL WLAN 5100.

Omron

The Japanese company Omron is well known for its innovative approach, the desire to use new technologies when creating new systems. This principle is used by the manufacturer in the creation of wireless solutions. When Omron released the WD30 wireless DeviceNet device, it was widely recognized for providing fieldbus capabilities (previously only available in a wired version) for short to medium range wireless communications.

Then Omron released the next modification of the DeviceNet wireless modem - WD30-01. The differences compared to the existing WD30 modem may seem minor, but they greatly expand the scope of these blocks. The antennas now have a magnetic base and a 2 meter cable. This allows the WD30 to be installed inside the case, extending the antenna out of the enclosure for more flexible use.

About the WD30 family

Omron's Wireless DeviceNet devices allow communication with any DeviceNet-compatible device via a fully wireless fieldbus. The WD30 is more than just a 1: 1 network extension device. One WD30 wireless master from Omron can access multiple slave devices.

Several wireless master devices can be located on the same DeviceNet network, forming complex flexible configurations in one system.

Technology used

DeviceNet wireless devices combine two of the latest wireless technologies: spread spectrum and antenna diversity. The wireless communication is based on Direct Sequence Spread Spectrum (DSSS) technology with 34 separate channels in the 2.4 GHz band. This frequency is allocated worldwide for use in industry, science and medicine (ISM). The use of spread spectrum technology reduces the impact of interference, ensuring the message gets through the first time.

All DeviceNet transceivers use a dual antenna system. It measures the output of a device by calculating the difference between the signal and its reflections. The transceiver automatically selects the antenna with the best signal quality to reduce interference.

Omron's DeviceNet wireless devices were the first commercially available wireless devices to combine these technologies.

Wide range of applications

Due to the characteristics of the cables, the topology requirements for DeviceNet cables typically limit the intermediate network length to six meters. However, some systems require noticeably more aboutlonger cable length. Omron's DeviceNet wireless network now allows data to be transmitted to DeviceNet nodes up to 60 meters from the backbone.

Low output power (10 mW) minimizes RF interference in other devices. The high operating frequency reduces the potential for electrical noise in the factory floor due to interference with the signals from DeviceNet wireless devices. Additionally, DeviceNet wireless devices have a built-in security function that prevents other users from changing parameters without knowing the codes. The setting procedure is the setting of a specific combination of switch positions that is difficult to repeat. Changing the positions of the switches does not change the configuration of the device.

The WD30 master and slave devices are equipped with a standard miniature DeviceNet connector, which expands the possibilities of DeviceNet applications in industrial environments. Such applications include material handling, conveyor systems, assembly lines, robocars and moving equipment where wires are not practical. DeviceNet wireless devices require a different skill set, slightly more knowledge, and more intensive training.

Among the advantages of wireless solutions from this manufacturer, we note the long-term reliable operation of radio modems (DeviceNet networks) in industrial workshops saturated with a variety of noise-generating equipment, such as voltage and current cutoff regulators, frequency converters, etc.

Omron DeviceNet WD30-01 Wireless Devices

Siemens

The capabilities of wireless networks are implemented in industrial communication systems (IMC - Industrial Mobile Communication), built on the corresponding components of SIMATIC NET, which are based on generally recognized world standards - IEEE 802.11, GSM, GPRS and UMTS.

The IMC encompasses the SI-MATIC NET software and hardware components that provide the ability to exchange data over the wireless links of Industrial Ethernet and PROFIBUS networks. SIMATIC NET components can be used to build a communication system for the entire company - from connecting a simple device to the network to organizing intensive data exchange between complex systems. Access points IWLAN (Industrial Wireless Local Area Network) of the SIMATIC NET family are capable of communicating with all mobile devices that meet the requirements of the IEEE 802.11 a, b, g, h standards.

SCALANCE W family

The SCALANCE W family unites in its structure a number of communication modules designed to build highly reliable IWLANs with deterministic data transfer times and support for redundant communication channels.

Such wireless networks make it possible to transmit through their channels both time-critical messages (for example, IWLAN with the transmission of emergency messages) and ordinary messages (for example, WLAN with the transmission of service and diagnostic messages). In general, such networks in terms of their functionality cover the requirements of the IEEE 802.11 standard.

SCALANCE W modules are manufactured in robust metal cases with IP65 protection degree, providing reliable protection against moisture and dust and the ability to use the modules in vibration and shock conditions.

All modules of the SCALANCE W series support standard user identification mechanisms to protect the IWLAN from unauthorized access, as well as encryption mechanisms for transmitted data.

Industrial execution

SCALANCE W modules are capable of maintaining their functionality in the temperature range from -20 ° C to + 60 ° C, being exposed to prolonged exposure to moisture and dust. The antennas, power supplies and connecting cables used in them are also designed for operation in an industrial environment.

Examples of using IWLAN

Wireless integration of PROFIBUS and PROFINET segments of stations into an existing Industrial Ethernet network is possible. For this, the required number of SCALANCE W access points are connected to the fixed Industrial Ethernet network.

Access points can be equipped with circular or directional antennas, as well as extended antennas with low radiation in the form of an RCoax cable. Any stationary or mobile objects equipped with client modules or IWLAN / PB Link PNIO modules can be connected to the wireless communication system via access points.

Let's give an example of implementation of remote configuration of equipment at mobile stations. Mobile stations move freely within the radio coverage area formed by two SCALANCE W788-1PRO access points. Each mobile station is equipped with a SCALANCE W746-1PRO client module. Support is provided for the wireless exchange of data between the operator panel, computer and programmable controller of each mobile station with the controller and HMI system of the Industrial Ethernet fixed network. The Field PG M programmer is used for remote maintenance of all equipment in this system.

Within the radio coverage area of \u200b\u200bone SCALANCE W788-1PRO or SCALANCE W788-2PRO access point, mobile stations with PROFINET IO distributed I / O components can be operated.

Software

The SINEMA E software package with a standard license provides support for the functions of automatic positioning of infrastructure components and optimization of communication channels, determines the required types of access points, and optimizes the values \u200b\u200bof their configuration parameters.

Supported Products:

WLAN access points: SCALANCE W788; W786; W784; HiPath AP2610, 2620, 2630, 2640; Wi-Fi 802.11 a / b / g / h access points.
WLAN client modules: SCALANCE W744; W746; W747; IWLAN / PB Link PNIO; Wi-Fi 802.11 a / b / g / h client modules.
LAN / WLAN adapters to support read / download functions: SIMATIC NET CP 1613 A2; CP 1612; standard LAN adapter; standard WLAN card.
WLAN adapter for performing measurements in WLAN; for measurements in standard mode - standard WLAN adapter; for advanced measurement mode - PCMCIA WLAN adapter.

One of the advantages of this manufacturer is the offer of sets of wireless devices compatible with the most popular PLCs and Siemens systems in the industry, providing noise-immune and reliable communication for process control systems in various industries, including transport.

Siemens SKALANCE W788-1PRO access point

Moxa

Moxa has developed and manufactures a large number of solutions for connecting various industrial devices with interfaces based on wireless technologies - IEEE 802.11 (WLAN) and GSM / GPRS / UMTS / HSDPA. Consider equipment for organizing direct, local networks without the participation of telecommunications providers (GSM, GPRS).

RISC computers with wireless interfaces

Moxa ThinkCore embedded computers are based on the RISC platform and are designed to create custom industrial automation applications. They have a software selectable RS-232/422/485 serial port, 802.11a / b / g interface for WLAN communication, SD slot, 2 USB and 1 Ethernet port. Moxa ART, 32-bit ARM9 processor, and embedded Linux provide a powerful and reliable platform for industrial environments with harsh environments, and is also a good solution for industrial M2M applications: communication, protocol conversion and remote device control and verification.

The following models are supplied to Ukraine: Moxa ThinkCore W311 (RISC-based embedded computer with WLAN, 1 serial port, LAN, Linux OS); Moxa ThinkCore W321 (RISC computer with WLAN, 2 serial ports, LAN, SD and Linux OS). Moxa ThinkCore W341 (RISC computer with WLAN, 4 serial ports, LAN, SD, USB, relay outputs, Linux OS).

RISC computers with multifunctional wireless interfaces

Moxa ThinkCore W311 UC-8481 series computers have 2 RS-232/422/485 serial ports, 2 Ethernet ports, 4 digital inputs and outputs, CompactFlash socket and 2 USB 2.0 ports. Moxa ThinkCore W311 UC-8481 is based on Intel XScale IXP435 533 MHz RISC processor. The computer has great computing and communication capabilities with very low heat dissipation.

Moxa ThinkCore W311 UC-8481 has seven connectors, which allows users to connect various wireless modules and GPS - this is very important, for example, for use on the railway and in general, on moving vehicles. Moxa also offers a model with an extended operating temperature range, from -25 ° C to 70 ° C, for harsh industrial environments.

Moxa ThinkCore W311 UC-8481 Embedded Computer

Wireless access controllers

The WAC-1001 industrial wireless access controllers are equipped with Moxa Turbo Roaming technology, which dramatically reduces roaming time for wireless devices - up to 50ms. This advanced feature provides high switching speeds and seamless connections, without interruptions or compromising wireless security, even in extremely harsh environments. The devices also feature IEEE802.11i (wireless security) support and a wide operating temperature range of -40 ° C to 75 ° C.

Wireless Access Points (AP / Bridge / AP Client)

Moxa offers a wide variety of similar devices. A typical example is the Moxa AWK-4131 - an industrial 3-in-1 wireless access point (Access Point / Bridge / Client) that allows users to provide high-speed, efficient wireless access to network resources using IEEE 802.11n technology with network speeds up to 300 Mbps. Moxa AWK-4131 uses two adjacent 20 MHz channels, combining them into one 40 MHz - for greater reliability and high throughput. The operating temperature range of the device is -40 ° C to 75 ° C.

The Moxa AWK-4131 has a redundant power input for increased equipment reliability and can also be powered over Ethernet (PoE). High-frequency modules Moxa AWK-4131 provide operation in two frequency ranges 2.4 and 5 GHz. The Moxa AWK-4131 are backward compatible with IEEE 802.11a / b / g standards, making them easy to integrate into existing infrastructure. IP68 enclosure and special M12 connectors protect the device from critical environmental conditions (dust, moisture)

IEEE 802.11 Wireless Access Devices (WLAN)

A typical representative of this group of equipment is a new series of MiiNePort W1 (Network Enabler) devices - Serial-Ethernet access server modules supporting IEEE 802.11 b / g wireless networks. They provide very easy connection of serial devices to wireless networks.

Moxa MiiNePort W1 provides speeds up to 921.6 Kbps over a serial port and supports a large number of different operating modes: RealCOM, TCP Server, TCP Client, UDP, RFC2217, as well as Infrastructure Mode (b / g) and Ad-Hoc Mode (b / g ) for IEEE 802.11 b / g wireless networks. High-quality driver support for the Moxa MiiNePort W1 makes it easy to integrate modules into existing solutions.

The Moxa MiiNePort W1 has a very compact size of 44.4 x 44.4 x 9.7 mm, as well as extremely low consumption (360 mA for 3.3 VDC, 290 mA for 5 VDC), which makes it easy to integrate into various serial devices to connect them to wireless networks.

Moxa MiiNePort W1 Serial-Ethernet Access Device

WLAN antennas

Moxa offers a wide range of antennas in various frequency bands (2.4; 5 GHz) and radiation patterns, from circular to directional. Gain ranges: 5 to 18 dBi.

Wireless equipment from Moxa is widely used in the creation of automated technical accounting systems, distributed monitoring systems and measurement of technological parameters in the food, paper, chemical industries, mechanical engineering, etc.

Moxa devices perform well in the construction of branched, locally distributed information, measurement and control systems, which is one of their key advantages.

You can read about the means of wireless data transmission in building automation systems in the 2nd part of the review, which will be published in July.

Wireless data transmission, in which signals are transmitted through air or space without any physical constraints, are becoming a popular alternative to physical transmission channels such as twisted pair, coaxial or fiber optic cable. Common technologies for wireless data transmission today include microwave transmission, communications satellites, pagers, cell phones, personal communications services (PCS), smart phones, personal digital assistants (PDAs), and mobile data networks.

The means of wireless transmission is the spectrum of electromagnetic waves shown in Fig. 8.3. Certain types of wireless transmission, such as microwaves or infrared, occupy specific spectral frequency ranges, measured in megahertz (MHz). Other types of wireless transmission are now widespread (for example, cell phones or paging devices), so in this case a specific frequency range is allocated, provided by national regulatory agencies, which is regulated by international agreements. Each frequency range has inherent advantages and disadvantages that make it easier to choose an area of \u200b\u200bits application.

Microwave systems,both terrestrial and airborne, transmit high-frequency radio signals through the atmosphere and are widely used to transmit large amounts of data over vast distances, from one point to another. Microwave signals are transmitted in a straight line and are not capable of bending around the curvature of the earth; therefore, long-range terrestrial transmission systems require transmission stations to be located 25 to 30 miles apart, which increases their cost.

This problem can be solved by bouncing microwave signals off satellites, which serve as relay stations for microwave signals transmitted from ground stations. Communication satellites are efficient (at the lowest cost) at transmitting huge amounts of information over ultra-long distances. Satellites are commonly used for communications in large, geographically dispersed organizations where cable systems or ground microwave stations are difficult to communicate. For example, Amoco uses satellites to transmit real-time data from offshore oil exploration. Research ships transmit the collected data using geosynchronous (geostationary) satellites to central computer centers in the United States in order to

most widely used by researchers in Houston, Tulse and the Chicago suburbs. In fig. 8.4 illustrates how this system works.

Conventional communication satellites rotate in stationary orbits about 22,000 miles from the Earth's surface. Recently, the latest satellite systems, the so-called LEO satellites, have been launched. These satellites are much closer to Earth and are able to pick up signals from low-power transmitters. These satellites also use less energy and are cheaper to launch than geostationary satellites. With such wireless networks, business people can travel anywhere in the world and have access to rich communications capabilities, including video conferencing and Internet access.

Other wireless transmission technologies are used in situations requiring remote access to corporate systems and mobile computing power. Paging systems have been in use for several decades, initially only by sounding an audible signal when a user, receiving a message, had to call back the office to inquire about the content of the

Microwave (microwaves / radio waves)

Transmission of large amounts of information over long distances from point to point by transmitting high-frequency radio signals through the atmosphere from one ground station to another.

Satellite (satellite channel)

Data transmission using orbiting satellites that serve as relay stations for transmitting microwave signals over very long distances.

Paging system

Wireless transmission technology, providing for the reception of radio signals by pagers, accompanied by the corresponding sound at the time of receipt of the message; used to transmit short alphanumeric messages.

messages. Currently, paging devices can send and receive short alphanumeric messages that the user reads on the pager screen. Paging is useful for communicating with mobile workers such as maintenance crews; one-way paging can also provide an inexpensive way to communicate with workers in offices. For example, Computer Associatesdistributes two-way pagers equipped with CA Unicenter control programs, which allow operators of computer networks to monitor the situation, as well as to quickly respond to emerging problems.

Cell Phonesoperate by transmitting / receiving radio waves to communicate with base stations located within adjacent geographic areas, called cells. The telephone signal is transmitted to the local cell, then it is transmitted from station to station (cell to cell) until it reaches the target cell, after which it is transmitted to the receiving phone. As the cellular signal moves from one cell to the next, the computer that

Cellular telephone (cell phone)

Personal communication services (PCS) (personal communication services)

Digital cellular technology that uses lower power, higher frequency radio waves than analog cellular technology.

Smart phone

A cordless telephone offering voice and text communication capabilities and an Internet connection.

ry monitors signals from cells, allocates a radio channel assigned to the next cell. Hexagonal honeycombs are typically eight miles in size, although they can decrease in densely populated areas.

Older cellular systems are analog and newer cellular systems are digital. Personal communications services (PCS) are a popular type of digital cellular service. PCS is completely digital in nature. It provides voice and data transmission, and uses a higher frequency range than is the case with analog cell phones. PCS cells are significantly smaller and more closely spaced than analog cells and can carry more traffic. In addition to voice communications, newer digital cell phones can handle voice mail, email, and faxes; save addresses; provide access to private corporate networks as well as the Internet. These smart phones are equipped with web browsers, which provide access to web pages containing text or other information (no graphics), which is convenient for devices with small screens. Some smart phone models have large screens as well as additional keyboards to make it easier to access the Internet. In ch. 9 details the application of these devices to provide wireless Internet access.

Pocket computers (PDAs) are small, touch-screen, portable computers that provide full digital data transfer capability. PDA devices have built-in wireless telecommunications capabilities as well as organizer software. A well-known example is the Palm VII plug-in organizer. This device allows you to exchange e-mail messages and also provides access to the Internet. Applications such as electronic planner, address book, and financial organizer are also supported. The device can accept data entered using the touchscreen stylus. The Organization Window describes the activities of Safeway, U. K., using a PDA in an e-commerce application to shop at a grocery store.

Personal digital assistants (PDA) (pocket computers)

Small touchscreen notebooks with built-in digital telecommunications capabilities.

Mobile data networks

Wireless networks that transfer data files two-way cheaply and efficiently.

Wireless networks specially designed for two-way transfer of data files are called mobile data networks.These radio wave-based networks transmit data generated by laptop computers. Another type of mobile data network is based on a series of transmitters built specifically for the transmission of text and data. Net Ardis(owned by American Mobile Satellite Corp.)is a public network that uses the described capabilities to organize two-way data transmission on a national scale. Company Otis Elevatorsuses the network Ardisto manage the movement of maintenance technicians across the country from an office in Connecticut. Professionals use this network to send generated reports.

Wireless networks and transmitting devices are more expensive, slower, and prone to errors than conventional LANs (Varshney and Vetter, 2000). However, major digital cellular networks are constantly increasing data rates (Chapter 9). (Owners of satellite systems like Teledesic spend billions on providing tremendous data rates over wireless networks associated with multimedia applications.) Ensuring optimal bandwidth and power consumption in wireless devices requires careful management, both technical and software. provision (Imielinski and Badrinath, 1994). Due to the fact that the radio signal can be easily intercepted, it becomes difficult to ensure security and secrecy (ch. 14),

Data cannot be transferred in its entirety between different wireless networks if they use incompatible standards. For example, the digital cellular service in the United States is supported by different carriers using one of several competing digital cellular technologies (CDMA, GSM 1900, and TDMA IS-136) that are incompatible with each other. Many digital cellular handheld receivers that use one of these technologies cannot operate in countries outside of North America; they operate on different frequencies with different sets of standards. A detailed discussion of these standards, as well as other network standards, is provided in Ch. nine.

Wireless technologies are used to transmit information over a distance between two or more points, without requiring their connection with wires. To transmit information, infrared radiation, radio waves, optical or laser radiation can be used.

Currently, there are many wireless technologies, most commonly known to users by their marketing names, such as Wi-Fi, WiMAX, Bluetooth. Each technology has certain characteristics that determine its field of application.

There are various approaches to classifying wireless technologies.

Range classification:

Wireless personal area networks WPAN (Wireless Personal Area Networks). These networks include Bluetooth.
Wireless local area networks WLAN (Wireless Local Area Networks). These networks include Wi-Fi networks.
Wireless metropolitan area networks WMAN (Wireless Metropolitan Area Networks). Examples of technologies are WiMAX.

Classification by applicationyu:

Corporate (departmental) wireless networks - created by companies for their own needs.
Operator wireless networks - created by telecom operators for the provision of paid services.

A concise but capacious way of classification can be the simultaneous display of the two most essential characteristics of wireless technologies on two axes: the maximum information transfer rate and the maximum distance.

A quick look at the most popular wireless technologies

Wi-Fi

Developed by the Wi-Fi Alliance consortium based on IEEE 802.11 standards, "Wi-Fi" is a trademark of the "Wi-Fi Alliance". The technology's name is Wireless-Fidelity, similar to Hi-Fi.

At the beginning of use, the installation of Wireless LAN was recommended where it was impossible or economically impractical to deploy a cabling system. At the moment, many organizations use Wi-Fi, since under certain conditions the network speed already exceeds 100 Mbps. Users can move between access points across the Wi-Fi coverage area.

Mobile devices (PDAs, smartphones, PSPs and laptops) equipped with client Wi-Fi transmitting and receiving devices can connect to a local network and access the Internet through access points or hotspots.

History

Wi-Fi was established in 1991 by NCR Corporation / AT & T (later Lucent Technologies and Agere Systems) in Nieuwegein, The Netherlands. Products originally intended for POS systems were introduced to the market under the WaveLAN brand and provided data transfer rates from 1 to 2 Mbps. Wi-Fi Creator - Vic Hayes ( Vic Hayes) worked in the team that participated in the development of the IEEE 802.11b, IEEE_802.11a and IEEE_802.11g standards. The IEEE 802.11n standard was approved on September 11, 2009. Its use allows to increase the data transfer rate by almost four times compared to devices of the 802.11g standards (the maximum speed of which is 54 Mbps), provided that it is used in 802.11n mode with other 802.11n devices. In theory, 802.11n is capable of delivering data rates of up to 480 Mbps.

Bluetooth

Bluetooth is a manufacturing specification for wireless personal area networks (eng. Wireless personal area network, WPAN).

The Bluetooth specification was developed by the Bluetooth Special Interest Group, which was founded in 1998. It includes Ericsson, IBM, Intel, Toshiba and Nokia. Subsequently, the Bluetooth SIG and the IEEE reached an agreement that made the Bluetooth specification part of the IEEE 802.15.1 standard (published June 14, 2002). Ericsson Mobile Communication began work on the creation of Bluetooth in 1994. This technology was originally tailored to the FLYWAY system's needs for a functional interface between travelers and the system.

The Bluetooth range can be up to 100 meters.

WiMAX (eng. Worldwide Interoperability for Microwave Access) is a telecommunication technology designed to provide universal wireless communication over long distances for a wide range of devices (from workstations and laptop computers to mobile phones). The technology was developed based on the IEEE 802.16 standard, also called Wireless MAN.

Scope of use

WiMAX is designed to meet the following challenges:

· Connection of Wi-Fi access points to each other and other segments of the Internet.

· Providing wireless broadband access as an alternative to leased lines and DSL.

· Provision of high-speed data transmission and telecommunication services.

Creation of access points that are not tied to geographic location.

WiMAX allows you to access the Internet at high speeds, with much greater coverage than Wi-Fi networks. This allows the technology to be used as "backbones", which are continued by traditional DSL and leased lines, as well as local networks. As a result, this approach allows the creation of scalable high-speed networks within entire cities.

WiMAX Standards Specifications

IEEE 802.16-2004 (also known as 802.16d or fixed WiMAX)... Specification approved in 2004. Supports fixed access in areas with or without line of sight. Consumer devices: fixed outdoor and indoor modems and PCMCIA cards for laptops. In most countries, this technology is allocated to the 3.5 and 5 GHz bands. According to the WiMAX Forum, there are already about 175 fixed version deployments. Many analysts see it as a competing or complementary technology for wired broadband DSL.

IEEE 802.16-2005 (also known as 802.16e and mobile WiMAX). The specification was approved in 2005 and is optimized to support mobile users and supports a number of specific features such as handover, idle mode and roaming. 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 pilot 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.