9 research outputs found
Max-min Fair Beamforming for SWIPT Systems with Non-linear EH Model
We study the beamforming design for multiuser systems with simultaneous
wireless information and power transfer (SWIPT). Employing a practical
non-linear energy harvesting (EH) model, the design is formulated as a
non-convex optimization problem for the maximization of the minimum harvested
power across several energy harvesting receivers. The proposed problem
formulation takes into account imperfect channel state information (CSI) and a
minimum required signal-to-interference-plus-noise ratio (SINR). The globally
optimal solution of the design problem is obtained via the semidefinite
programming (SDP) relaxation approach. Interestingly, we can show that at most
one dedicated energy beam is needed to achieve optimality. Numerical results
demonstrate that with the proposed design a significant performance gain and
improved fairness can be provided to the users compared to two baseline
schemes.Comment: Invited paper, IEEE VTC 2017, Fall, Toronto, Canad
Outage performance analysis of cell-center/edge users under two policies of energy harvesting
In this paper, two energy harvesting policies deploying in cooperative non-orthogonal multiple access (NOMA) systems are considered. After period of wireless power transfer, the NOMA users including cell-edge and cell-center users simultaneously transmit the superposition coded symbols to the base station (BS). In the last time slot, the BS decodes to achieve its signal based on superposition coded symbol with corresponding power allocation factors. This paper provides exact expressions of outage probability in two schemes. Performance gap of two NOMA users can be raised by providing different power allocation factors. It is confirmed by numerical result. Distance and data rate are main factors affecting outage performance. Scheme I exhibit scenario where power beacon transmits energy signal to NOMA user while the BS feeds energy to NOMA user in Scheme II. It is shown that outage performance of Scheme I is better than that of Scheme II.Web of Science254807
Enhancing PHY Security of MISO NOMA SWIPT Systems With a Practical Non-Linear EH Model
Non-orthogonal multiple-access (NOMA) and simultaneous wireless information
and power transfer (SWIPT) are promising techniques to improve spectral
efficiency and energy efficiency. However, the security of NOMA SWIPT systems
has not received much attention in the literature. In this paper, an artificial
noise-aided beamforming design problem is studied to enhance the security of a
multiple-input single-output NOMA SWIPT system where a practical non-linear
energy harvesting model is adopted. The problem is non-convex and challenging
to solve. Two algorithms are proposed to tackle this problem based on
semidefinite relaxation (SDR) and successive convex approximation. Simulation
results show that a performance gain can be obtained by using NOMA compared to
the conventional orthogonal multiple access. It is also shown that the
performance of the algorithm using a cost function is better than the algorithm
using SDR at the cost of a higher computation complexity.Comment: This paper has been accepted by ICC 2018 worksho