No abstract

In this paper, we consider a two-user downlink full-duplex (FD) non-orthogonal multiple access (NOMA) relay system where the FD relay uses an energy harvesting (EH) technique to assist the communication between the base station and far user over flat, independent and non-identically Rayleigh fading channels. Importantly, since the relay operates in FD mode, we take into account the effect of the interference caused by relay on the near user. Considering this EH-FD-NOMA relay system, we derive the exact mathematical expressions of the outage probabilities and ergodic capacities of near and far users. Monte–Carlo simulations verify the accuracy of our analytical method. Numerical results provided in this paper allow system designers to clearly see not only the impacts of the power distribution factor and the self-interference cancellation capacity of the relay but also the influence of the strength of inter-user interference at the near user on the outage performances and ergodic capacities of both users.

No abstract

In this paper, we evaluate two-way relay communication systems in cognitive radio environments. The proposed model includes two subsystems: a primary system and a secondary system. The primary system consists of a primary transmitter and a primary receiver while the secondary includes two terminals exchanging their data via an intermediate relay node. Each network node is equipped with a single antenna and operates under a half-duplex mode. The channel state information (CSI) interference from the secondary node to the primary receiver is assumed imperfect. Using analytical methods, this paper derives the interference probability from the secondary system to the primary receiver and an optimal back-off control power coefficient for the secondary transmitter. To evaluate the secondary system quality, an explicit expression for the system outage probability (OP) and its closed form in the high signal-to-noise region (SNR) is presented. Theoretical results are verified using Monte-Carlo simulation.

No abstract