In the United States, the FCC defines regulations for unlicensed bands as 902 to 928 MHz and 2400 to 2483.5 MHz.
Licensed Vs. Unlicensed
|License required to be purchased
|License is free
|Medium can be accessed\used only by the owner of the license
|Unlicensed spectrum and its medium can be accessed\used by anyone
|Permission is required for transmission or reception and scheduling
|Anyone can access the medium if channel is empty
|Interference management is carried out by careful frequency planning
|Interference management can be done using various techniques such as distributed management
|Advantages- The benefits of licensed spectrum is known and predictive interference
|Advantages- Free or low cost to use, available nearly everywhere, scalable
|Disadvantages- high costs for network operators, requires central management, low scalability
|Disadvantages- Unpredictable interference (due to lack of QoS), Higher load, Lack of protection from interference due to other systems
For FCC Basics of Unlicensed FCC Basics of Unlicensed
Transmitters click here.
For the National Association of Broadcasters Engineering Handbook, click here.