Carrier frequencies are part of the microwave portion of the electromagnetic spectrum and are employed for point-to-point and point-to-multipoint communication. Different types of carrier frequencies are utilized for specific purposes and to avoid interference. Here are some common types of carrier frequencies used in telecom microwave links:
Licensed Bands: Licensed bands are frequency ranges assigned by regulatory authorities to specific network operators or service providers. These bands are typically allocated for commercial telecom services and are used for long-distance point-to-point microwave links. They offer protection against interference and are subject to regulatory oversight to ensure reliable and interference-free communication.
Unlicensed Bands: Unlicensed bands are open for use by anyone without the need for a specific license. The most common unlicensed bands used for microwave links include the 2.4 GHz and 5.8 GHz bands. These bands are often used for short-distance, high-capacity wireless links and are popular for building-to-building or campus connectivity.
ISM Bands (Industrial, Scientific, and Medical): Some microwave links operate in the ISM bands, which are unlicensed and intended for non-communication purposes but are used for certain short-range wireless data links and other applications. The 2.4 GHz ISM band is an example.
Millimeter-Wave Bands: Millimeter-wave frequencies, typically above 24 GHz, are used for high-capacity, short-distance microwave links. These links are often employed in urban areas for point-to-point or point-to-multipoint connections, offering very high data transfer rates.
E-Band (70/80 GHz): The E-band, also known as the “light-licensed” band, is used for high-capacity, short-distance links that require a license but are easier to obtain than traditional licensed bands. E-band links are often used for backhaul connections in metropolitan areas and for high-speed, high-frequency trading applications.
V-Band (60 GHz): V-band is another millimeter-wave band used for short-distance, high-capacity communication. It is suitable for applications like wireless gigabit Ethernet and wireless video transmission.
Sub-6 GHz Bands: In addition to higher microwave frequencies, some microwave links operate in the sub-6 GHz range, particularly in the 3.4-3.8 GHz and 5G bands. These frequencies are suitable for long-distance communication and are used for backhaul connections in mobile networks.
Microwave carrier frequencies offer a number of advantages over other radio frequencies, including:
- High bandwidth
- Long range
- Directionality
However, microwave carrier frequencies also have some disadvantages, including:
- Line-of-sight propagation
- Interference
