Dynamic spectrum access (DSA), consisting of spectrum sharing and spectrum trading stage, becomes a promising approach to increase the efficiency of spectrum usage and system performance.
In this case, the SUs receive new information that changes the perception of the spectrum usage.
This adaptation is based on the current observation of the spectrum usage by primary users.
This helped us in observing the variation in spectrum usage across different angles of arrival.
According to spectrum utilization report of FCC [1], there is a large variation in spectrum usage intensity that some bands are heavily used, while others have light usage.
A decrease in spectrum usage efficiency and, therefore, in the performance of the affected SUs.
In other words, a HeNB should be able to operate in either the mode of co-channel spectrum usage or the mode of dedicated-channel spectrum usage.
Reports are requested within 180 days from various Executive branch departments and agencies on "their anticipated future spectrum requirements," as well as reviews of their current spectrum usage.
Then, we categorize the existing distributed DSA protocols based on different criteria, such as spectrum sharing modes, spectrum allocation behaviors, spectrum access modes, the usage of common control channel, spectrum usage strategies, the number of radios, and spectrum sensing techniques.
All three histograms depict the spectrum usage probability of PUs at different instances of time.
Opportunistic spectrum usage is one of the main goals of a cognitive radio.
