Gee, What’s the Big Deal About 5G?

(For Geeks Only)
By Joe Callison
6 April 2020

There is much confusion, misunderstanding, and even conspiracy theories about 5G cellular communication. The “G” in 5G does not stand for gigahertz like your router. It does not stand for gigabit speed like your internet service. It is simply a new generation of cellular technology involving new radio hardware and new software techniques that allow more efficient use of the available frequencies and new frequencies that are being added for cellular communications.  

Summarizing how cellular communication technology has evolved, the first generation was analog voice only. The second generation introduced digital voice. The third generation brought mobile data (text services). The fourth generation introduced mobile internet service. The fifth generation promises (eventually) higher data rates, lower latency (lag in transmitting and processing data), and connection to more simultaneous devices, whether for communications or sensors and smart devices or future uses we have not even thought of yet.

Ignore the current hype from cellular carriers about 1 to 2 gigabit internet speeds on new 5G phones. Even 4G phones are capable of up to 2 Gbps. AT&T advertises 5G Evolution, for example, which is not 5G at all but actually just enhanced 4G. The performance of actual 5G services already offered in some cities depends on the frequency spectrum used, and the highest speed services are being reserved for business customers at this time.

The highest speeds are available from a high frequency band, generally in the 20 to 100 GHz range. This newly available frequency band allows communication channels that are 5 times wider than the channels available for 4G (100 MHz instead of 20 MHz) and can be combined for up to 800 MHz of total bandwidth per user compared with 160 MHz for 4G. Wider channels means a higher capacity to transmit data. Current average download speeds from carriers range from 300 to 800 Mbps. Unfortunately, the higher frequencies do not travel far, about 800 feet between towers, and have poor penetration through walls and windows. It is this previously unused spectrum of high GHz frequencies that is the subject of conspiracy theories and concerns about possible health risks.

The mid-frequency band being used for 5G is in the 1 to 10 GHz range. This range covers most existing cellular communications for 4G and extends slightly higher into newly available frequencies. Current average download speeds reach 200 Mbps on channels that are 100 MHz wide. The distance between towers is typically around half a mile. Penetration into buildings is better than for the high frequency band.

The low-frequency band is less than 1GHz and has narrow channels of only 10 MHz. This band is already crowded with existing 4G and television signals, but the signals travel very far with good penetration into buildings. Average download speeds can approach 150 Mbps and the cost to deploy nation-wide coverage is the least for this band.

Carriers are using a mixture of these three bands as they build out their 5G services, since each band is suited for different parts of the network. For now it is mostly being used in conjunction with existing 4G. It may be a few more years before there are nation-wide stand-alone 5G networks, but gigabit speeds for everyone everywhere may be expecting too much, at least for the next several years. The 5G standard currently is defined as having 100 Mbps or faster downloads for individual users, after all. It is the radio on the tower that serves many users that can handle up to 20 Gbps downloads. These performance standards are expected to be revised over the years as the technology matures.


Posted by Joe Callison

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