152 research outputs found
Joint Transceiver Design Algorithms for Multiuser MISO Relay Systems with Energy Harvesting
In this paper, we investigate a multiuser relay system with simultaneous
wireless information and power transfer. Assuming that both base station (BS)
and relay station (RS) are equipped with multiple antennas, this work studies
the joint transceiver design problem for the BS beamforming vectors, the RS
amplify-and-forward transformation matrix and the power splitting (PS) ratios
at the single-antenna receivers. Firstly, an iterative algorithm based on
alternating optimization (AO) and with guaranteed convergence is proposed to
successively optimize the transceiver coefficients. Secondly, a novel design
scheme based on switched relaying (SR) is proposed that can significantly
reduce the computational complexity and overhead of the AO based designs while
maintaining a similar performance. In the proposed SR scheme, the RS is
equipped with a codebook of permutation matrices. For each permutation matrix,
a latent transceiver is designed which consists of BS beamforming vectors,
optimally scaled RS permutation matrix and receiver PS ratios. For the given
CSI, the optimal transceiver with the lowest total power consumption is
selected for transmission. We propose a concave-convex procedure based and
subgradient-type iterative algorithms for the non-robust and robust latent
transceiver designs. Simulation results are presented to validate the
effectiveness of all the proposed algorithms
Robust Sum-Rate Maximization in Transmissive RMS Transceiver-Enabled SWIPT Networks
In this paper, we propose a state-of-the-art downlink communication
transceiver design for transmissive reconfigurable metasurface (RMS)-enabled
simultaneous wireless information and power transfer (SWIPT) networks.
Specifically, a feed antenna is deployed in the transmissive RMS-based
transceiver, which can be used to implement beamforming. According to the
relationship between wavelength and propagation distance, the spatial
propagation models of plane and spherical waves are built. Then, in the case of
imperfect channel state information (CSI), we formulate a robust system
sum-rate maximization problem that jointly optimizes RMS transmissive
coefficient, transmit power allocation, and power splitting ratio design while
taking account of the non-linear energy harvesting model and outage probability
criterion. Since the coupling of optimization variables, the whole optimization
problem is non-convex and cannot be solved directly. Therefore, the alternating
optimization (AO) framework is implemented to decompose the non-convex original
problem. In detail, the whole problem is divided into three sub-problems to
solve. For the non-convexity of the objective function, successive convex
approximation (SCA) is used to transform it, and penalty function method and
difference-of-convex (DC) programming are applied to deal with the non-convex
constraints. Finally, we alternately solve the three sub-problems until the
entire optimization problem converges. Numerical results show that our proposed
algorithm has convergence and better performance than other benchmark
algorithms
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