Home > What are Spectrum Bands and how do they work?

What are Spectrum Bands and how do they work?

What are Spectrum Bands and how do they work?

Radio communication has been a fundamental aspect of our daily lives for several decades now. Whether it be mobile phones, television, or wireless internet, the communication infrastructure is powered by electromagnetic waves, also known as the spectrum. In this article, we’ll take a look at the significance of spectrum bands, the implications of spectrum interference, and the impact of spectrum bands on the 5G revolution.

What Are Spectrum Bands?

When a device transmits a signal, it sends out electromagnetic waves at a specific frequency within a spectrum band. The signal can be received by another device that is tuned to the same frequency, allowing for communication between the two devices. The availability of specific frequency ranges for communication enables devices to operate in an organized manner and reduces the risk of interference between different types of communication.

A thought through choice of spectrum bands is essential for good communication based on your project, infrastructure, goals and needs. Indeed, different types of communication require different amounts of bandwidth, and therefore different frequency ranges. For example, higher frequency ranges provide more bandwidth and can carry more data, making them ideal for high-speed data transmission, such as 5G mobile networks. Lower frequency ranges, on the other hand, can cover larger distances, making them ideal for television broadcasting and long-range communication.

Can any spectrum band be used by anyone?

No, Spectrum bands are classified into two categories: licensed and non-licensed.

Licensed Spectrum Bands

Licensed spectrum bands are frequency ranges that are exclusively assigned to a specific user or organization for a specific purpose. The user or organization is granted a license to use the spectrum band for a specified period and must comply with the regulations set by the regulatory authority. Some of the most common licensed spectrum bands include cellular (700 MHz and 800 MHz), PCS (1.9 GHz), AWS (1.7/2.1 GHz) and BRS/EBS (2.5 GHz). The advantages of licensed spectrum bands include:

  • Reliable and consistent: Licensed spectrum bands provide dedicated bandwidth, ensuring consistent and reliable communication for the user.
  • High-quality service: The exclusive use of the spectrum band ensures that the user can provide high-quality service to its customers.
  • Priority access: Licensed spectrum bands have priority access to the spectrum in case of spectrum scarcity.

However, Licensed Spectrum Bands can be costly for very large areas. Obtaining a license for a spectrum band can be expensive, as regulatory authorities auction off the rights to use the spectrum. Once a license is granted, the user cannot change the purpose for which the spectrum is being used.

To cover a small area, for instance, the french Regulatory association (ARCEP) requests reasonable  fees which depend on different variables listed in the law.

Non-Licensed Spectrum Bands

Non-licensed spectrum bands are frequency ranges that can be used by anyone without the need for a license. Some of the most common non-licensed spectrum bands include the following: ISM (Industrial, Scientific, and Medical) bands (900 MHz, 2.4 GHz, and 5 GHz), Unlicensed National Information Infrastructure (U-NII) bands (5 GHz), and Short-Range Devices (SRD) band (433 MHz), CBRS (Citizens Broadband Radio Service – 3,5 GHz).

Non-Licensed Spectrum Bands are cost-effective as there is no cost associated with using non-licensed spectrum bands, making them an attractive option for low-cost communication solutions. Non-licensed spectrum bands can be used for a variety of purposes, allowing for greater flexibility in their use.

However, non-licensed spectrum bands are shared with other users, leading to the risk of interference and reduced reliability and they do not provide dedicated bandwidth, leading to variations in the quality of service.

How to Deal with Spectrum Spectrum Interference

Spectrum Interference refers to the degradation or disruption of communication on a particular frequency band due to the presence of other signals on the same or adjacent frequency bands. Interference can occur from a variety of sources, such as other communication devices, electronic devices, or naturally occurring phenomena such as solar flares.

Interference can have a significant impact on the quality of communication on a specific frequency band. For example, if a communication signal is weak, it may be overpowered by an interfering signal, leading to a drop in signal quality and reduced communication reliability. In some cases, interference can lead to complete signal loss, making communication impossible. To mitigate interference, several techniques can be used, such as the following:

  • Frequency allocation: Allocating different frequency bands for different types of communication can reduce the risk of interference between signals.
  • Frequency reuse: Reusing frequency bands in a specific geographic area can reduce the risk of interference between signals.
  • Power control: Limiting the transmission power of communication devices can reduce the risk of interference with other signals.
  • Directional antennas: Using directional antennas can reduce the risk of interference by directing the transmission of the signal in a specific direction.
  • Private Networks: Deploying a private network is the most efficient way to avoid interference as the private network users would be the only one using it.

What About Spectrum Band Reallocations ?

Spectrum band reallocations refer to changes made to the allocation of frequency bands over time due to emerging technologies or new regulations. These changes are necessary to meet the growing demand for spectrum resources, provide additional bandwidth for new technologies, and improve the efficiency of existing systems.

Over time, advances in technology have resulted in the development of new communication systems that require additional bandwidth. For example, the rollout of 5G networks has created a significant demand for additional spectrum resources, leading to changes in spectrum allocations to accommodate this new technology.

Regulations also play a role in spectrum band reallocations. The regulatory authority may decide to open up previously restricted spectrum bands for public use, allocate additional bandwidth for specific purposes, or change the allocation of a particular frequency band to meet new regulatory requirements.

One example of a recent spectrum band reallocation is the opening up of the C-Band (3.7-4.2 GHz) (CBRS -Citizens Broadband Radio Service) for 5G use in the United States. The Federal Communications Commission (FCC) allocated this spectrum band for use by the mobile industry to support the deployment of 5G networks, which require a large amount of bandwidth.

The 5G revolution has been a significant driver of the growth of new technologies and has had a profound impact on the spectrum. Spectrum bands are essential for enabling effective communication between devices. Understanding spectrum bands allocation, spectrum interference and spectrum reallocations is important in order to take full advantage of their features.