For this reason, the distance between eNodeBs and the primary system may change from one site to other.
Upon establishing a credit system, the secondary transmitters alternate between relaying for the primary system and accessing the spectrum for their own use.
If the spectrum band is not being used by the primary system or if communications between CR devices do not cause any harmful impact on the performance of the incumbent users, then CR nodes can adaptively coexist with primary users based on sensing schemes [3 6].
The interactions between the primary and the secondary systems in a three-tier CRN can be modeled by a Stackelberg game [12], where the primary system is the leader and secondary system is the follower.
Establishing a platform for collaboration between the primary healthcare system, EPI, and NRAs for health products was a challenge in most countries.
In [28], the cooperation between a primary system and a cognitive system in a cellular network was studied, where the cognitive base station relays the primary signal using an amplify-and-forward relaying or a decode-and-forward relaying protocol, and in turn, it can transmit its own signal.
In this study, we focus on the cross-tier interference management between a primary system (PS) and a secondary system (SS) in a spectrum-shared scenario.
This includes, in particular, the lead-water steam generators, which have a main role in the feedback between the primary and secondary system and whose operation has to satisfy, beside common requirements on steam pressure and temperature, additional physical constraints, like a lower limit of the feedwater temperature to avoid lead freezing in any operating condition.
"There is a very strong link between the primary health care system and community caregivers.
