IEEE 802.11ac - Wi-Fi 5

the family of standards Wi-Fi 802.11 develops Institute of electrical and electronic engineers and electronics (Institute of Electrical and Electronics Engineers, IEEE). The standard provides data transfer rate to 1.1 Gbps and above. The standard provides data transmission for mobile devices on one radio channel with a speed up to 350 Mbps. Such speeds are reached owing to use of broad band of radio frequencies 80 MHz or 160 MHz in the range of 5 GHz, more noise-free in comparison with 2.4 GHz. The IEEE 802.11ac standard was developed for ensuring high capacity of a wireless local area network. It promises gigabit wireless speeds for consumers.

The original project of technical specification 802.11ac was confirmed by the working group (TGac) last year while ratification of Wi-fi Alliance is expected at the end of this year. In spite of the fact that standard 802.11ac so far in project stage also should be still ratified by Wi-fi Alliance and IEEE, we already begin to see the products of gigabit Wi-Fi available in the market.

Characteristics of the standard of new generation of Wi-fi 802.11ac:

WLAN 802.11ac uses a number of new methods for achievement of a huge gain of performance to theoretically supports the gigabit potential and ensuring high throughputs, such as:

• 6GHz band
• The high density of modulation is up to 256 QAM.
• More wide bandwidths - 80MHz for two channels or 160MHz for one channel.
• To eight Multiple Input Multiple Output of space flows.

Multi-user MIMO of low power consumption 802.11ac put new problems for development of the engineers working with the standard. Daley we will discuss these problems and available solutions which will help new product development, based on this standard.

More wide bandwidth:

802.11ac has more wide bandwidth of 80 MHz or even 160 MHz in comparison with previous to 40 MHz in standard 802.11n. More wide bandwidth leads to improvement of the maximum capacity for digital communication systems.

Among the most difficult tasks of design and production there are a generation and the analysis of signals of wide bandwidth for 802.11ac. Testing of the equipment capable to process 80 or 160 MHz for check of transmitters, receivers and components will be required.

For generation of 80 MHz of signals, many RF generators of signals have no rather high frequency of sampling for support of a typical minimum 2X resampling ratios which will give as a result necessary images of signals. Using the correct filterings and resampling of a signal from Waveform of the file, it is possible to generate 80 MHz signals with good spectral characteristics and EVM.

For generation of signals of 160 MHz, with the broad range the generator of wave signals of any form (AWG), such as Agilent 81180A, 8190A can be used for creation of analog I/Q of signals. These signals can be applied to external I/Q. As inputs of the vector generator of signals for frequency conversion of RF. Besides, it is possible to create 160 MHz signals using 80 +80 MHz of the mode supporting standard for creation of two segments 80 MHz in separate MCG or ESG signal generators, having integrated then radio signals.

MIMO:

MIMO is use of several antennas for performance improvement of the communication system. You could see some Wi-Fi of access point having more than one antenna which is sticking out of them - these routers use MIMO technology.

Check of MIMO of constructions is change. Multichannel generation and the analysis of signals also verifications of projects can be used for idea of the capacity of MIMO devices and assistance in troubleshooting.

Amplifier of Linearity:

The amplifier of Linearity is characteristic and the amplifier using whom the signal output of the amplifier remains correct to an input signal in process of increase. Really amplifiers of linearity are linear only to a limit after which an exit is saturated.

There are many methods for improvement of linearity of the amplifier. Digital pre-emphasis is one of such to the technician. Design automation of the software as SystemVue provides the application which simplifies and automates digital design of pre-emphasis for power amplifiers.

Compatibility with the previous versions

Though standard 802.11n is used already for many years, still many routers and wireless devices of older protocols 802.11b and 802.11g also work. As well upon transition to 802.11ac, old Wi-Fi standards will be supported and to be provided backward compatibility.

Devices it is standard 802.11ac:

Gigabit wireless solutions of standard 802.11ac for Wi-Fi of routers and consumer electronics were already presented to consumers at the Electronics Show (CES) exhibition this year.

It is expected that household appliances will become the first in the market of gigabit wireless devices of standard 802.11ac, and some suppliers, already announced availability of such products.

Products based on new Wi-Fi of the standard begin to appear in the market. But their quantity is still not enough to justify upgrade of network. The similar situation was observed with standard 802.11n in 2006.

In the last several months, it was much written about new 802.11ac the standard. The new generation of Wi-fi promises to be very interesting as with 802.11ac, having higher capacity and a connectivity of bigger number of users at the same time, some critical obstacles which users 802.11n face today will be overcome.

Work on 802.11ac in the range 5GHz offers transmission rate to 1300 Mbit which is ideal for a continuous streaming video of HD and at the same time Internet access. Along with gigabit speeds, 802.11ac products are delivered with the improved opportunities of RF raised by reliability.

2015: The Ministry of Telecom and Mass Communications legalized 802.11ac

The Ministry of Telecom and Mass Communications published the order which approves rules of use of the equipment Wi-Fi of standard 802.11ac and 802.11ad. Department also supports expansion of frequency bands in the range of 5 GHz for use of standard 802.11ac without restrictions, however the State Radio Frequency Commission (SCRF) should make this decision.

The order of the Ministry of Telecom and Mass Communications No. 129 "About making changes in Rules of use of the equipment of a radio access. Part І. The rules of use of the equipment of a radio access for wireless data transmission in the range from 30 MHz to 66 GHz approved by the order of the Ministry of Telecom and Mass Communications of the Russian Federation of 9/14/2010 No. 124 r", it was signed by the head of department Nikolai Nikiforov on April 22, 2015 on May 14 the document was registered in Ministry of Justice, and on May 18 it was published on the official Internet portal of legal information Ðravo.gov.ru. The order will become effective 10 days later after the publication.

Standard 802.11ac works in the frequency range of 5 GHz in frequency bands 5150-5350 MHz, however for operation of radio-electronic devices (distribution zone) of standard 802.11ac without restrictions it is necessary to expand this frequency band.