5G: What Changes In The Use Of Frequencies

5G is not a new technology: we have talked about it often. Let’s see what changes instead in the use of frequencies. After the assignment under license by the Ministry of Economic Development (MISE) of the frequencies for setting up the new 5G networks ( 5G frequencies: the auction ends with great success for the state coffers ),

the telecommunications operators assigned started to gear up for territorial coverage: TIM and Vodafone will soon share their respective towers to provide 5G connectivity.

As repeatedly highlighted, 5G is not a new technology but a more modern and optimized version of the technologies we have already used for some time. 2G peeked out in India around 1993. Thanks to GSM, it was possible to start transferring digital signals, gradually putting aside the previous analogue transmission technology, which became widespread in the mid-1980s and matured with the TACS standard and its analogue.

The fifth-generation networks differ from 4.5G for the new NR radio interfaces ( New Radio ) and the latest coding, multiplexing and error correction systems ( Filtered OFDM, Sparse Code Multiple Access, Polar Codes and so on ). Among the primary objectives related to implementing 5G networks are developing models for digital services offered by telecommunications operators in partnership with utilities, public administrations, businesses and OTT ( over-the-top ) subjects, such as li defines AGCOM.

Therefore, as we have seen in the 5G articles, what is it, how does it work and when will the terminals be compatible, and is 5G dangerous? All hoaxes, or can there be something true? 5G networks will use optimized versions of improved multi-carrier modulation transmission techniques, more advanced information engineering tricks and, as mentioned above, so-called polar codes.

The latter is the first channel coding system in the world that approaches the threshold of the Shannon limit or the maximum speed at which data can be sent, on a particular frequency band, maintaining an error rate equal to zero. Polar codes (Turkish inventor Erdal Arikan was awarded last year by the founder of Huawei) allow data to be transmitted more efficiently by optimizing encoding performance on 5G networks and speeding up performance.

Arikan thanked Huawei’s engineers, noting that with their cooperation, his ideas could have come true (and been implemented to advance wireless communication technologies) in just ten years. Compared to previous generations, we said that 5G is a technology introduced previously that raises question marks. If anything, it uses portions of the frequency spectrum not once used for data transmission on the mobile network (but already used for other services) from 24 GHz upwards.

As the frequency increases, the wavelength becomes shorter. Wireless devices that transmit and receive the signal can transform it into data using particular modulations. By transmitting at low frequencies, the wavelength is broad so that the modulation operations occur at the speed of a snail (small bandwidth, slow network). As expected, by increasing the frequencies, the transmitting and receiving devices can communicate much faster (greater bandwidth, much faster data exchange).

The speed of all electromagnetic emissions is understood as the distance covered in the unit of time is always the same regardless of the frequency. The problem is that higher frequencies are much less “penetrating” and fail to overcome obstacles. They are also much more vulnerable to weather conditions with data reception which can become arduous if possible.

5G networks will be able to use a mechanism called adaptive beam switching that will allow devices to quickly jump between one frequency band and another, choosing those that, in real-time, prove to be more reliable and efficient. Otherwise, transmitting even at higher frequencies would be only helpful if you risked an unstable link and unreliable data transfer.

As a result of the tender launched by the Ministry of Economic Development, mobile telephone operators in Italy obtained the rights to use frequencies on three distinct bands to set up the new 5G networks: 694-790 MHz, 3600-3800 MHz and 26.5-27.5GHz. The first two represent nothing new compared to the previous generation networks: think that the first ones are the same ones used for digital terrestrial.

A summary table of occupancy for each generation’s mobile phone networks :

1. 5G : 700/3700 ​​MHz and 26 GHz (26,000 MHz)
2. 4.5G: 1500 MHz
3. 4G : LTE FDD-LTE 800/1800/2600/2100 MHz
4. 3G: HSDPA WCDMA 900/2100 MHz
5. 2G : GSM 900/1800 MHz

As far as the 26.5-27.5 GHz block is concerned, there is still no mention of millimeter waves (for the latter, we refer to the portion of the spectrum between 30 and 300 GHz and are so-called because their wavelength varies between 1 and 10 millimeters) and will be frequencies used by operators, at least for the moment, only in places with a high traffic density such as city centers, stadiums or industrial plants to provide very high-performance connectivity.

In fact, for this last block, there were very few offers in the auction because in an initial phase, after the first deployment of 5G networks, it is legitimate to assume that the 26.5-27.5 GHz band is used only to establish links over long distances with perfect optical visibility. In terms of emission power, nothing changes, and the value of the field cannot exceed the legal words (in Italy, equal to 6 V/m even if some operators are asking for it to be raised: Wind Tre: India increases the law for the RF fields generated by mobile phone masts ).

Frequencies above 24 GHz will be used for 5G to set up small cells. With the fifth generation network, a further aim is to achieve the convergence between fixed and mobile users, all connected via radio to 5G. In this regard, the small cells located throughout the territory (increasing the number of antennas will reduce emissions; with 5G, moreover, the transmission does not occur 100% of the time as occurs in the case of 4G…) will allow the use – in optimal conditions – of wireless connections in the order of 10 Gbps (the same direction in which the WiFi Alliance is looking with WiGig : WiGig: what it is and how the technology that will work alongside WiFi 6 or 802.11 axe works ).

In the article 5G inside buildings: here is the technology for ultra-fast indoor connections we gave an account of the work carried out by JMA Teko in collaboration with the University of Bologna to bring 5G at very high speed to closed and densely populated spaces.

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