Joint Transmit Power and Relay Two-Way Beamforming Optimization for Energy-Harvesting Full-Duplex Communications

Abstract

Abstract-This paper studies the joint optimization problem of two-way relay beamforming, the receiver power splitting (PS) ratio as well as the transmit power at the sources to maximize the achievable sum-rate of a simultaneous wireless information and power transfer (SWIPT) system with a full-duplex (FD) multipleinput multiple-output (MIMO) amplify and forward (AF) relay, assuming perfect channel state information (CSI). In particular, our contribution is an iterative algorithm based on the difference of convex programming (DC) and one dimensional searching to achieve the joint solution. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm. I. INTRODUCTIONTraditionally, wireless communication systems use a timedivision or frequency-division approach to bidirectional communication. This involves dividing the spectral resources into orthogonal component resulting in half-duplex (HD) communication. Recent advances, nevertheless, suggest that fullduplex (FD) communication that allows simultaneous transmission and reception of signal over the same radio channel be possible [1]. Since radio signals that carry information can also be used as a vehicle for transporting energy, the emergence of FD technology brings a new opportunity for simultaneous wireless information and power transfer (SWIPT) [2], [3]. A practical application of SWIPT technology is seen in battery-limited devices such as sensor nodes mounted at some inaccessible or difficult-to-access locations [4], [5].Recently, much interest has turned to FD relaying in which information is sent from a source node to a destination node through an intermediate FD relaying node. In the literature, relay aided SWIPT systems have been largely considered for HD relaying [6]. Recently, the authors in [7] considered SWIPT in FD relaying where only the relay node works in FD mode. Most recently, [3] considered SWIPT in FD multipleinput multiple-output (MIMO) relay system and used a power splitting (PS) relaying approach with fixed transmit power at the source nodes. However, the transmit power in FD systems affects the self-interference (SI) and careful optimization is necessary in order to maximize the achievable rate.

Secure Full-Duplex Two-Way Relaying for SWIPT

“…Clearly, the relay's transmit covariance is indeed a complicated function of W. In this letter, we adopt the zeroforcing (ZF) solution constraint to cancel the RSI from the relay output to the relay input via the optimization of W [13]. In particular, the ZF constraints may take the following forms [16]…”

“…We proceed to investigate the optimal power solution (P A , P B ) assuming W, Q and ρ all being fixed. Evidently, it is easy to check that at the optimum, at least one source will be transmitting with maximum power [13] i.e., P A = P max or P B = P max . As a consequence, we can relax (23) into two sub-problems with: (i) P A = P max , (ii) P B = P max .…”

A Scalable Performance-Complexity Trade-off for Full Duplex Beamforming

“…In [6], the ergodic capacity of a FD relays was investigated, where the FD relay harvests a portion of the received signal from the source node to power itself. Similarly, [7] studies the joint optimization problem of two-way relay beamforming with energy harvesting to maximize the achievable sum rate of the FD system.…”

Beam-domain hybrid time-switching and power-splitting SWIPT in full-duplex massive MIMO system

“…According to (29) and using the bounding technique in [58], the average achievable rates at the downlink user g u,k can be expressed as (44) at the top of the next page. The transmit power of sensor g e d,k is set to p g e u,k…”

“…Since FD can potentially double the wireless physical layer capacity, recently, the transceiver design problem in FD SWIPT systems has arised. In [44], the joint optimization problem of relay beamforming, the receiver PS ratio as well as the transmit power at the sources are investigated for SWIPT system with a FD MIMO AF relay to maximize the system achievable sum rate. The design of robust nonlinear transceivers for MIMO FD wireless-powered relay networks is studied in [45], where the effects of imperfect channel state information (CSI) is took into consideration.…”