Robust Transceiver Optimization for Power-Splitting Based Downlink MISO SWIPT Systems

Abstract

This letter considers a downlink multi-input single-out (MISO) system where each user performs simultaneous wireless information and power transfer (SWIPT) based on a power splitting receiver architecture. Assuming imperfect channel state information (CSI) at the base station, we develop two robust joint beamforming and power splitting (BFPS) designs that minimize the transmission power under both the signal-to-interference-plus-noise ratio (SINR) and energy harvesting (EH) constraints per user. In the first design, we consider the worst-case (WC) SINR and EH constraints, and show that the WC-BFPS problem can be relaxed as a semidefinite program (SDP) through a linear matrix inequality representation for (infinitely many) robust quadratic matrix inequality constraints. In the second design, we consider the chance constraints (CCs) for SINR and EH, and resort to both semidefinite relaxation and Bernstein-type inequality restriction to transform the CC-BFPS problem into another convex SDP. Based on these convex reformulations, the (near-)optimal robust BFPS designs can be efficiently solved. Numerical results are provided to demonstrate the merit of the proposed robust designs.Index Terms-Bernstein-type inequality, energy harvesting, power splitting, robust beamforming, semidefinite program.

Robust Optimization with Probabilistic Constraints for Power-Efficient and Secure SWIPT

“…The derived safe approximations lead to tractable semidefinite programmes (SDPs) which are convex and serve as performance upper bounds for the original minimization problem. This paper differs from the related works in [11], [12] in the following aspects. Communication security was not considered in [11].…”

“…This paper differs from the related works in [11], [12] in the following aspects. Communication security was not considered in [11]. While this paper studies a secure SWIPT wireless system, [12] considered a secure SWIPT cognitive system.…”

“…This conservative design approach requires an exceeding amount of system resources to protect rarely occurring worst cases. Hence, less conservative approaches have recently been proposed by accepting the violation of the QoS constraints with certain probabilities [11], [12]. This paper focuses on power-efficient transmission strategies for SWIPT by minimizing the total transmit power.…”

“…Hence, the approach in [12] is less secure than the proposed approaches. Also, the optimization problem considered in this paper is more challenging than its counterparts in [11], [12] as secure information transmission for multiple IRs is ensured whereas the problem in [11] does not consider secrecy at all and the problem in [12] protects only a single IR.…”

On Secrecy Performance of MISO SWIPT Systems With TAS and Imperfect CSI

“…In [25], the joint multicast transmit beamforming and receive PS problem was investigated for MISO SWIPT systems to minimize the transmit power of the transmitter subject to signal-tonoise ratio (SNR) and EH constraints at each receiver, while considering both scenarios of perfect and imperfect CSI at the transmitter. In [26], a downlink MISO SWIPT system was considered with imperfect CSI at the transmitter and two robust joint beamforming and PS designs were developed to minimize the transmission power under both the SINR and EH constraints per user. Considering the imperfect CSI of idle secondary receivers and primary receivers, the authors of [29] studied the resource allocation algorithm design for cognitive radio secondary networks with simultaneous wireless power transfer and secure communication based on a multiobjective optimization framework.…”