Spectrum Management - Spectrum Use

Spectrum Use

Spectrum management is a growing problem due to the growing number of spectrum uses.

Over the air broadcasting, which started in 1920.

Government and Research which include defense, public safety (maritime, air, police), resource management, transport, radio astronomy, ...

Commercial services to the public (voice, data, home networking)

Industrial, scientific and medical services which include Telemedicine, remote control, ...

In the 80s, the only concern was about radio and television broadcasting ; but today mobile phones and wireless computer networks are more and more important as fewer than 15% of US households rely on over the air Broadcasting to receive their TV signals.

The US spectrum is managed either by the FCC for non-governmental applications or by the NTIA for governmental applications. For shared application, both entities should agree.

The spectrum is divided into different frequency bands, each having a specific application. For instance, the frequency band that covers 300 kHz to 535 kHz is reserved for aeronautical and maritime communications and the spectrum from 535 kHz and 1605 kHz for AM radio. This process is called Allocation.

The next step is to assign frequencies to specific users or classes of users. Each frequency band has a specific assignment that depends on the nature of the application and the numbers of users. Indeed, some applications require a wider band than others (AM radio uses blocks of 10 kHz where FM radio uses blocks of 200 kHz). In addition, "guard bands" are needed to keep the interference between applications to a minimum.