Wireless communication technology

The principle of Wi-Fi technology is as follows: a chip is built into the device, which can give reliable wireless synchronization with another of the same chip. If there are more than two devices, then an access point must be used.

The ten most promising wireless technologies of the future

In five years, new wireless data technologies will change our world. Unmanned cars will become safe and entertain passengers, wireless charging will become convenient, Internet of Things sensors will be able to work autonomously for years, robots and virtual assistants will be able to better distinguish their surroundings and voices, geo-positioning accuracy will grow to one meter. And there will even be new interior designs. Here are ten promising wireless technologies that, according to Gartner, will dominate corporate and residential networks in the future.

Over the past two decades, wireless technology has managed to displace many traditional means of communication and information transfer. In the next five years, new types of wireless communications are expected to become the basis for the development of promising technologies, such as robotics, autonomous land and air transport, and medical gadgets.

The existing wireless solutions are being improved and adjusted to the needs of new generation developments. In some cases, on the contrary, the emergence of fundamentally new promising technological trends dictates the need to develop unusual communications with specific requirements for power, energy savings, software control, great autonomy.

Research firm Gartner has analyzed key trends and identified ten wireless technologies that will dominate the market as the next generation of enterprise architectures.

Wi-Fi networks

Wi-Fi networks are today and will remain the basis of high-performance networks for home and office at least until 2024. In addition to its traditional role, the technology will find application in new developments. For example, as the basis for radar systems or as an element of next-generation two-factor authentication systems.

At the end of 2018, the cross-industry group Wi-Fi Alliance announced the launch of a new version of the standard – IEEE 802.11ax, which was marketed as Wi-Fi 6. The new standard is compatible with previous versions and supports the 2.4 GHz and 5 GHz bands. Wi-Fi 6 devices will support Orthogonal Frequency Division Multiple Access (OFDMA). This means synchronous data transmission to multiple clients at the same time at an average speed. In addition, the combined operation of MU-MIMO and OFDMA technologies will support up to eight connections at up to 11 Gb/s. In Wi-Fi 5 the number of such connections did not exceed four.

The new Target Wake Time feature of Wi-Fi 6 will provide the ability to set a sleep schedule to conserve battery power.

The introduction of Wi-Fi 6 will significantly increase the density of wireless networks, improving the quality of data exchange in public places with a large number of users per unit area – in transport, corporate offices, trading halls, hotels and stadiums. The first commercial launches of Wi-Fi 6 are scheduled for late 2019.

Wireless technology standards

• WWAN – wireless global networks. The most common type of such networks are GPRS networks, which cover tens of kilometers.
• WMAN – wireless networks of urban scale. They transmit information over distances of up to several kilometers. To this group belong WiMAX networks.
• WLAN – wireless local area networks. They provide the transmission of information at a distance of several tens to several hundreds of meters. Networks of Wi-Fi belong to this category.
• WPAN – personal wireless networks. They are used to keep computers, telephones, office equipment and other devices connected. The effect of the network extends up to a few tens of meters. Bluetooth networks belong to this group.

In addition to supported range wireless technologies are subdivided depending on the communication standards used. Consider the most popular standards GPRS, Bluetooth, NFC, Wi-Fi, WiMax.

GPRS

The GPRS standard makes it possible to access the Internet from anywhere in the world where cellular network coverage is available. The standard is provided by mobile operators. It is available to users of cellular phones and modems that support GSM connection. The service is charged based on the volume of data transmitted. The time spent by the user in the network is not included in the cost calculation.

Bluetooth

Bluetooth technology makes it possible to connect two devices wirelessly, e.g. cell phones, telephone and computer, etc. Depending on conditions, data transfer via Bluetooth is possible up to a distance of 100 meters.

NFC

The NFC standard supports the transfer of traffic over short distances of up to 20 cm. However, the transmission speed is much higher than with Bluetooth.

Today, NFC technology is actively used in mobile devices. In particular, the NFC-chip on the phone can be used for contactless payment for purchases and services, used as an electronic ID card, an electronic ticket, a key for access to a room or a vehicle. The standard provides a high degree of security for the wireless technology, as the data is stored on a separate chip.

Access point

The key device for building Wi-Fi networks is the Wireless Access Point (WAP). It is a base station that creates a connection between the user device and the existing wired or wireless network (most often providing Internet access). It also connects all the devices connected to it into a new wireless network, which allows communication between them even without Internet access.

The radio signal from the access point can pass through walls, doors, windows, and other building structures. With this user device, you don't have to be within line of sight of the network equipment to connect.

In most cases, a Wi-Fi router performs the function of the access point. Modern router models broadcast a signal in a line-of-sight range of about 100 meters. However, the signal strength may be reduced if there are obstacles in the way of its passage, such as concrete floors, metal structures, etc.

Development of wireless communication between computers

In 1968, scientists at the University of Hawaii began work on the project THE ALOHA SYSTEM. The main purpose of the project was to test the possibility of using radio communications instead of wired connections to interconnect computers on the same network.

A little about the context. The project itself was implemented in Hawaii, an archipelago in the central Pacific Ocean. The original plan was to integrate educational institutions from the islands of Kauai, Oahu, Maui, and Hawaii (yes, the Hawaiian archipelago includes the island of Hawaii) into one network. The computing center was located in the main building of the University of Hawaii near Honolulu. The distance to it from the other hubs was up to 300 km. The idea of running a cable was not even considered.

The realization of the scientists' idea was based on short-range radio communication. The resulting wireless communication system was called AlohaNet. There were two versions of this network: pure and discrete.

Pure Aloha

With a pure system, each of the terminals would send data as soon as it appeared. Of course, this approach caused collisions and frame losses. To detect collisions, the central computer, after receiving a frame, would send it back to the senders. If the sender detected a collision, it would wait for a random interval of time and send the frame again. The central computer used a broadcast antenna and the terminals used a directional antenna. This way they did not receive transmissions from other senders.

Pure Aloha went live in 1971, becoming the first wireless network between computers. A year later the system was upgraded to double its performance.

Discrete Aloha

The method of data transfer in a discrete system was based around slots (or clock cycles). Each terminal was allocated a time slot (corresponding to the time of one frame) to send data. A special synchronization signal was used to synchronize at the beginning of each interval.

IEEE: advent of the workgroup

NCR wanted Vic Hayes to make an offer to IEEE on behalf of the company. But Vic did not agree to such terms: he wanted to remain independent. The company agreed, and in 1988 Vic Hayes asked the IEEE for input on a wireless communications standard. It turned out that the existing committee was inactive and the chairman left.

Because Vick was not promoting an already patented solution from NCR, he was able to gain credibility and form the 802.11 working group. Ethernet and WaveLAN technologies became part of the technical base of the committee, which began its work in 1990. The first standard known as 802.11 was formed 7 years later.

The history of wireless communications

It is well known that A.S. Popov was the inventor of the radio, but at that time information data was sent through the radio in the form of telegraphic signals. Then came the communication system based on radio telephones. Then it became possible to use radio waves to transmit images, and television broadcasting emerged. Further progress in telecommunications led to the development of wireless network technologies, which are divided into the following types, which differ in the range of radio signal transmitters:

1. PAN (Personal Area Network, which means personal networks). This is a network with a small coverage area (about ten meters).
2. WLAN (Wireless Local Area Network, which means wireless local area network).The range is about a hundred meters.
3. WWAN (wide area wireless networks). This network uses wireless communication, which provides Internet access to mobile users.
4. Technological technique of Wi-Fi (Wireless fidelity, i.e. wireless communication). Today, such network organization technologies are the most in demand with high demands on mobility, convenient implementation and use. This standard appeared in the ninety-seventh year of the twentieth century and is considered the standard for broadband wireless communication, with a series of 802.11. As a rule, Wi-Fi devices are used to organize wireless local computer networks, and in addition, to form a separate node for access to the Internet at higher speeds.

Wi-Fi wireless data transmission standard

As noted earlier, under the technology of Wi-Fi is understood one of the ways of transmitting information via radio. This technology is now the most widespread in the world's leading powers and is rapidly developing in the Russian Federation. It allows users to connect without any wired connections to the Internet. Wi-Fi technology was invented in Holland by NCR Corporation/AT&T. Originally such a system was designed for use in cash register systems and was introduced as WaveLAN. It was capable of supporting information exchange at about two Mbit/sec. At the end of 2009, the IEEE 802.11n standard was approved, which made it possible to increase the speed of information exchange in Wi-Fi network by up to four times, if compared to equipment using the 802.11g standard. Theoretically, 802.11n allows communication speeds of up to 600 Mbps.

The use of this technology allowed all users of computer devices to appreciate the advantages of mobile Internet at home, at work or in public places, because they had the opportunity to move around. All owners of mobile computer devices with built-in Wi-Fi module can connect to the Internet at rather high speeds of information exchange.

As noted earlier, Wi-Fi technology is based on the use of radio waves. Radio waves are electromagnetic oscillations that propagate at speeds close to the speed of light. Their main parameters are pulse frequency, wavelength and radiated power. The full frequency range used for radio communication is divided into a set of frequency bands located in the range from about thirty Hertz to three thousand Gigahertz. Wireless Wi-Fi networks, according to a set of 802.11b,g,n standards, can use a frequency range of 2400 to 2483.5 MHz. That is, the centimeter frequency range.

VoWiFi technology from a Wi-Fi perspective

We're used to cellular and Wi-Fi existing separately from each other. But sometimes it happens – we get inside a room where there is definitely no cellular service, but there is Wi-Fi. At the same time, it's still possible to make phone calls. How does it work?

VoWiFi (Voice over Wi-Fi) is a technology that allows cellular users to make voice calls in areas where there is no cellular coverage, but there is Wi-Fi coverage. It requires the following:

Most Russian cellular carriers support VoWiFi. At the end of the article, there are links to instructions on how to enable this technology, as well as lists of supported devices. Manufacturers indicate support for this technology in the specifications of the device.

If you are planning to change your smartphone, it is better to choose a device with both VoWiFi support and 802.11ax/ac support for the 5GHz band. First, they will be able to reach you even if you are "off the grid". And second, the 2.4 GHz band is extremely noisy, and it almost always has interference problems, which often causes Wi-Fi to "perform poorly" as opposed to the more "free" 5 GHz band.

When your smartphone registers on the network via VoWiFi, a corresponding indication appears in the status bar. Depending on the model of your smartphone, the display and icons may look different. In our case (Huawei smartphone), the icons in the status bar look like this:

In the picture above, both SIM cards are registered in the operator's network in two ways: both through the cellular network (signal strength indicators, one with an "R" icon – roaming) and through VoWiFi ("VoWiFi" icons). As a rule, when there is a VoWiFi connection, the name of the operator's network changes from "Operator" to "Operator-WiFi". In our case, the names are not displayed because there is not enough space in the status bar. Additional indication also appears on the call button, when calling and in the call list:

And now let's move on to the technical component

Let's take a closer look at VoWiFi traffic from a Wi-Fi network perspective. For the tests, we created an open Wi-Fi network without encryption and did a radio capture using Wireshark when a mobile device was connected to it.

WARNING: Just in case, let me remind you that in terms of information security, it is highly undesirable to use open networks in real life! Use (PSK) or other security methods.

ePDG (Evolved Packet Data Gateway) gateway is an element of the cellular operator's infrastructure that allows a mobile device (smartphone) to establish a connection to the operator's network when connected through unprotected communication channels, including the internet. For security purposes the traffic between the mobile device and the ePDG is encapsulated in an IPSec tunnel and encrypted. After association with a Wi-Fi network and obtaining an IP address, the mobile device identifies the IP address of the cellular operator's ePDG gateway serving the SIM card. It uses a special kind of FQDN (domain name) regulated by 3GPP standards. Each cellular operator has a unique PLMN-Id (Public Land Mobile Network – identifier). This identifier includes the country code (Mobile Country Code, MCC) and the operator's network code (Mobile Network Code, MNC). These codes are unique, and for each operator the FQDN of the ePDG gateway will look like this:

The links contain lists of MCCs of different countries and MNCs of RF operators, and at the end of the article there are domain names and IP addresses of ePDG gateways of the largest RF operators. DNS response to this format address request contains one or more IP addresses of the ePDG gateway. If your smartphone has SIM cards of several operators that support VoWiFi, DNS requests are sent for each operator.

Next, the mobile device initiates an IPSec tunnel to the gateway at the address received from the DNS response. Below is a screenshot from Wireshark showing an example of establishing an IPSec tunnel between a smartphone and an ePDG. Host 192.a.b.c is the smartphone (VoWiFi client) and host 213.d.e.f is the cellular operator's ePDG gateway.

LTE

This standard is currently the most promising along with other global networks. Mobile broadband gives the highest wireless packet data rates. In terms of operating frequency bandwidth, everything is ambiguous. The LTE standard is very flexible, networks can be based in the frequency range from 1.4 to 20 MHz.

The range of networks depends on the height of the base station and can reach 100 km. The ability to connect to networks is provided to a large number of gadgets: smartphones, tablets, laptops, game consoles and other devices that support this standard. The devices must have an LTE module built in, which works together with the available GSM and 3G standards. In the event of an LTE connection interruption, the device will switch to the available access to 3G or GSM networks without dropping the connection.

As for the data transfer speed, we can note the following: compared to 3G networks, it has increased by several times and reached 20 MBit/s. The introduction of a large number of gadgets equipped with LTE modules ensures the demand for this technology. New base stations are being installed, which provide high-speed Internet access even in populated areas remote from megacities.

Let us consider the principle of operation of the fourth generation networks. Wireless packet transmission technology is carried out using the IP protocol. For fast and stable synchronization between the base station and the mobile station is formed as a frequency and time duplex. Due to a large number of combinations of paired frequency bands broadband connection of subscribers is possible.

The spread of LTE networks has reduced mobile tariffs. A wide range of network coverage allows operators to save on expensive equipment.

Data transmission devices

In our daily lives, we are surrounded by devices that function based on wireless data transmission technology. And each device has several activity modules of one or another standard. For example: a classic smartphone uses GSM, 3G, LTE networks to transmit packet and voice data, Wi-Fi to access the Internet via an access point, Bluetooth to synchronize the device with accessories.

Let's look at the most popular wireless data devices, which have become ubiquitous:

1. Wi-Fi router. This device is capable of providing Internet access to multiple devices. The device itself is synchronized with the Internet source through a wired connection or with the help of a SIM card of the cellular network operator.
2. Smartphone. A versatile means of communication that allows you to transmit voice information, send short text messages, access the Internet, and synchronize with wireless or wired accessories.
3. Tablet PC. Functionally can be identical to a smartphone. A distinctive feature is a large screen, which makes using the gadget more comfortable for certain types of work.
4. Personal computer. It is a fully functional stationary device with built-in operating system, allowing to work in Internet networks, including wireless ones. Wireless data transfer to the computer from the access point is usually carried out via Wi-Fi-adapter which is connected via USB socket.
5. Laptop. A smaller version of a personal computer. Most laptops have a built-in Bluetooth adapter and Wi-Fi module, allowing you to sync to access the Internet and connect wireless accessories without additional USB adapters.
6. Wireless accessories and peripherals. This category includes wireless speakers, headphones, headsets, mice, keyboards, and other popular accessories that connect to your devices or computers.
7. TV or Smart-TV. A TV with an operating system functionally resembles a computer, so having built-in wireless modules for it is a necessity.
8. Game console. This gadget has wireless access to the Internet to install software. Game consoles are synchronized with the device using Bluetooth technology.
9. Wireless Smart Home equipment. A very complex and versatile system, which is controlled wirelessly. All sensors and equipment elements are equipped with special modules for signal transmission.

Examples of Wireless Technology Implementation in Russian Industry

Case 1. A petrochemical company uses expensive American equipment which requires special maintenance involving quite rare and expensive specialists. At a certain stage, due to sanctions, American specialists were not able to come to production and carry out routine maintenance. The company realized that considerable resources were needed to train its own specialists. Moreover, there were no guarantees that ready specialists would not be poached by competitors. To solve this problem, it was decided to install special microphones: they "listen" to the work of the power units via radio waves, determining in what state the units are and when it is better to stop them for maintenance. Problems detected by the program are marked and sent to the vendor for examination. This eliminates the need for constant monitoring of equipment and on-site technicians. Data is transferred using the Cisco Ultra-Reliable Wireless Backhaul solution. As a result the customer can efficiently monitor the operation of the equipment. Transition to new technology will allow avoiding dependence on occasional specialists and reducing the payroll.

emphasized Pavel Zhokin, the head of the Central region for the development of IoT sales channels at Cisco.

Case 2. One of the metallurgical enterprises has implemented a system to monitor the movement of scrap metal. The peculiarity of the solution is that the information is transmitted from the cameras mounted on the rail cranes that load scrap metal. The cameras (there are five at each site) transmit a continuous video stream thanks to a Cisco URWBH solution. In fact, the client company received a video analytics system that can recognize the numbers of cars bringing in scrap metal, as well as the numbers of cars in which the metal is loaded. The cameras evaluate the occupancy of trucks and railroad trains as they enter and exit. After unloading scrap metal from railroad cars and vans, cameras read the number of each car and license plate number of each van, determine the level of loading (at the entrance of the shop), the condition of trains and trucks after unloading scrap metal (came full, left empty, not half empty). This eliminates situations of theft of scrap metal and staff negligence (e.g., loading earth instead of scrap metal).

Overview of wireless technologies

Each of the wireless technologies on the market has its own characteristics. The choice of one or another solution depends on the tasks the enterprise faces.

Wi-Fi is one of the available and universal technologies. It can be used to transfer large amounts of data quickly, but the range of coverage is very limited. As a rule, Wi-Fi is not suitable in cases where it is necessary to ensure communication from a mobile moving object, when it is necessary to work with complex applications and when data transmission delays will be critical for the customer.

If it is fundamentally important for a company to minimize data packet loss, it is better to use MESH technology, which provides no more than 5 ms delay. Building an MESH infrastructure is more complex and expensive than in the case of Wi-Fi, but networks based on MESH have a higher range (1-2 km, compared to only 300-500 m with Wi-Fi). MESH supports high data transfer speeds – up to 200 Mbit/s, which is much higher than that of private LTE (pLTE).

Many companies choose pLTE, but it should not be forgotten that deploying such networks requires dedicated frequencies and requires expensive infrastructure (both in terms of equipment cost and network ownership cost). In any case, pLTE is not suitable when the volume of transmitted data increases significantly on the infrastructure.

The LoRaWan technology stands out. It is responsible for collecting data from a wide range of sensors. For example, it is needed to regularly check the level of humidity, lighting, door status (opening / closing), etc. LoRaWan also collects statistical data about the equipment in the form of a sequence of all possible indicators (engine hours, amount of fuel in the tank of a diesel generator, etc.). One base station here can cost dozens of times less than in the case of pLTE. But the bandwidth of LoRaWan is quite small – only 10-50 kbit/s, which means that this technology is designed to transmit small amounts of data.

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