2 research outputs found
Joint Beamforming Design and Time Allocation for Wireless Powered Communication Networks
This paper investigates a multi-input single-output (MISO) wireless powered
communication network (WPCN) under the protocol of harvest-then-transmit. The
power station (PS) with reliable power supply can replenish the passive user
nodes by wireless power transfer (WPT) in the downlink (DL), then each user
node transmits independent information to the sink by a time division multiple
access (TDMA) scheme in the uplink (UL). We consider the joint time allocation
and beamforming design to maximize the system sum-throughput. The semidefinite
relaxation (SDR) technique is applied to solve the nonconvex design problem.
The tightness of SDR approximation, thus the global optimality, is proved. This
implies that only one single energy beamformer is required at the PS. Then a
fast semiclosed form solution is proposed by exploiting the inherent structure.
Simulation results demonstrate the efficiency of the proposed algorithms from
the perspectives of time complexity and information throughput.Comment: 9 pages, 3 figures, submitted to IEEE Communications Letter
DEBIT: Distributed Energy Beamforming and Information Transfer for Multiway Relay Networks
In this paper, we propose a new distributed energy beamforming and
information transfer (DEBIT) scheme for realizing simultaneous wireless
information and power transfer (SWIPT) in multiway relay networks (MWRNs),
where multiple single-antenna users exchange information via an
energy-constrained single-antenna relay node. We investigate the optimal
transceiver designs to maximize the achievable sum-rate or the harvested power.
The resultant sum-rate maximization problem is non-convex and the global
optimal solution can be obtained through a three-dimensional search in
combination with conventional convex optimization. To reduce the computation
complexity, a suboptimal DEBIT scheme is also proposed, for which the
optimization problem becomes linear programming. The achievable sum-rate
performance is analyzed and a closed-form lower bound is derived for the MWRN
with a large number of users. Furthermore, we consider the harvested-power
maximization problem under a target sum-rate constraint, and derive a lower
bound of the average harvested power for MWRNs with a large number of users.
Numerical results show that the DEBIT scheme significantly outperforms the
conventional SWIPT and the derived lower bounds are tight.Comment: 8 page