Figure 1
From: SoRoute: a reliable and effective social-based routing in cognitive radio ad hoc networks
Network model. The laptops are denoted as primary users, and the cell phones represent secondary users. The dotted circles denote the interference range of PUs or SUs. In this example, there is a primary network with one PU base station and four primary users as well as a cognitive radio ad hoc network. Each PU is allocated a specific sub-channel. According to Definition 1, both SU 1 and SU 2 detect that c h a n n e l 1 is available, therefore c h a n n e l 1 is a common channel for their message transmission.