The primary network is a network that owns a licensed radio band and the secondary network is a network which wants to use the same band without causing any harmful interference to the primary network.
Note: In the ABR problem formulation, it is possible to allow multiple sessions to use the same band rather simply (thereby eliminating constraint (18)), without separating the power for the sessions as P ij m ( q ), q ∈ Q.
The one-hop user is mainly interfered by the neighboring BSs and the interfering sources of a two-hop user are all the RSs which use the same band with its serving RS. Figure 1 Two-hop cellular network.
There are two reasons for incorporating this constraint: (i) It results in a much simpler formulation than if multiple PUs were allowed to use the same band; and (ii) it allows a different QoS parameter to be set for each PU if desired.
In order to create these new applications, CR differentiates between two kinds of users: primary users (PUs), those who are licensed users, and secondary users (SUs), those who try to use the same bands when they detect a spectral hole.
For the in-band relay deployment, on the left side, all the nodes are served using the same frequency band f1, and the segregation is maintained in the TD (data not shown in the figure).
Two frequency reuse patterns are considered: the FR1 pattern in which all cells are active simultaneously; and the FR3 pattern, in which three groups of access points are active simultaneously on three orthogonal bands (e.g., cells 8, 10, 12, 14, 16, and 18 are simultaneously using the same frequency band).
All satellites transmit their data using the same frequency band, gathered on the ground by stations within the visibility circle.
This is caused by neighboring cells using the same frequency band.
