What are 'low' and 'mid' bands? And what does 'electromagnetic frequency waves' even mean?
Imagine a pebble falling into calm water and causing ripples on the surface. The duration between each high point of two successive waves is its frequency. To explain this more formally – in physics and technology, frequency is a measure of how fast the repetitions of a periodic process follow each other, e.g. in a continuous oscillation. The frequency of electromagnetic waves is measured in hertz (Hz), named after the renowned physicist Heinrich Hertz, who accomplished scientific breakthroughs in his research on electromagnetism. One hertz is defined as one cycle per second.
The waves used for telecommunication purposes are in the part of the electromagnetic spectrum ranging from 100 kHz up to 300 GHz. The spectrum could be considered a public good that is a valuable asset for the cost-efficient deployment of wireless networks with indoor and outdoor coverage.
Two frequency ranges (low and mid) have been identified for mobile communication use by the ITU: A third range (high band) is the high range, which is currently not used for mobile communication in Europe.
Frequency Range 1 (FR1) covers frequency bands up to 7 GHz. These bands are in use by 1G to 4G networks, and two of the three 5G pioneer bands in Europe (694-790 MHz – called the 700 MHz-Band; 3.4-3.8 GHz – called the 3.6 GHz-Band; and above FR1, 24.25-27.5 GHz – called the 26 GHz-Band). The maximum channel bandwidth defined for FR1 is 100 MHz, due to the scarcity of continuous spectrum in this crowded frequency range. The band in this range that is most widely used for 5G in Europe is the 3.6 GHz-band.
Frequency Range 2 (FR2) reaches up to a maximum of 33.4 GHz in Europe. In other parts of the world higher bandwidths are in use, up to 90 GHz. Bands in this range are called millimetre wave ranges, which have a shorter range, but higher available bandwidth compared to FR1. The minimum channel bandwidth defined for FR2 is 50 MHz, and the maximum is 400 MHz. The higher the frequency, the greater the ability to support high data-transfer speeds.
Network operators use millimetre waves for their additional capacity and higher throughput. However, due to their shorter range than microwaves, more antennas are needed to cover the same area. Millimetre waves are also almost completely unable to pass through objects like buildings – even a person’s skin can block them. As a rule of thumb, the low-frequency range below 1 GHz offers good coverage but limited capacity, and the high-frequency range above 26 GHz offers high capacity but limited coverage.
The frequency bands for communication purposes have been auctioned to operators in Europe by the individual member states, following the guidelines set by the EU Commission. Operators also can share frequencies to ensure citizens have access to a mobile network from their individual devices. Licensed Shared Access (LSA) and Authorised Shared Access (ASA) are concepts based on allowing use of the spectrum licensed for mobile telecommunications by more than one entity.