… efficiency, cognitive radio (CR) has been proposed as … users (CUs) to share the spectrum
licensed to primary user (PUs) [10]. Basically, there are three spectrum sharing strategies in CR …

… effectiveness of the proposed scheme in guaranteeing the primary security in CR networks.
… Thus, we propose this secure primary transmission scheme assisted by a secondary NOMA …

… 1 demonstrates a relay-aided CR-NOMA network having a primary source PS and several
intermediate relays {Rk|k = 1, 2, ..., K} employing relaying protocols [31], [32], [33], ie DF …

… We consider an uplink CR-NOMA system consisting of a primary user U0, a secondary
user U1, and a base-station (BS). Each node is equipped with a single antenna. The channel …

… design of NOMA transceivers … NOMA can be found in recent survey articles [17]–[20]. This
paper focuses on a cognitive radio (CR) inspired NOMA network, where multiple primary users …

… and Um are treated as the primary and secondary users in the m -th time slot, respectively, …
the implementation of NOMA is transparent to the primary user, the secondary user’s signal is …

… a CRNOMA uplink system, we analyse the probability to allocate a primary and a secondary
user … in the way the primary user behaves, whereas they significantly differ in the secondary …

… outage performance for all NOMA users. The key … primary CR-NOMA users considering
practical system limitations in terms of HIs, imperfect CSI and SIC. Besides, ensuring that primary …

… in the power domain to serve the user with a better channel condition. In [8], … CR with NOMA
and describe that the user having a poor channel condition is considered as a primary user (…

… CR-NOMA network under the secrecy constraint of primary … Different from the overlay
CR-NOMA networks introduced in [3]… of primary users when viewing the secondary users as Eves. …