The Performance of Wireless Powered MIMO Relaying With Energy Beamforming

Abstract

Abstract-This paper analyzes the performance of energyconstrained dual-hop amplify-and-forward (AF) relaying systems with multi-antenna nodes, in the presence of multiple co-channel interferers (CCI) at the destination. To maximize the overall signal-to-interference-plus-noise ratio (SINR) as well as the harvested energy so as to mitigate the severe effects of fading and enable long-distance wireless power transfer, hop-by-hop information and energy beamforming is proposed where the transmitted signal is steered along the strongest eigenmode of each hop. The wirelessly powered relay scavenge energy from the source information radio-frequency (RF) signal through energy beamforming, where both the time-switching receiver (TSR) and power-splitting receiver (PSR) are considered, then uses the harvested energy to forward the source message to the destination. To this end, tight lower and upper bound expressions for the outage probability and ergodic capacity are presented in closed-form. These are employed to investigate the throughput of the delay-constrained and delay-tolerant transmission modes. In addition, the asymptotic high signal-to-noise ratio (SNR) outage probability and ergodic capacity approximations are derived, where the achievable diversity order is also presented. Numerical results sustained by Monte Carlo simulations show the tightness of the proposed analytical expressions. The impact of various parameters such as energy harvesting time, power-splitting ratio, source transmit power and the number of antennas on the system throughput is also considered.Index Terms-MIMO relaying, half-duplex relaying, beamforming, maximum ratio transmission (MRT), maximum ratio combining (MRC), zero-forcing (ZF), wireless power transfer, energy harvesting, outage probability, ergodic capacity.

Hop-by-Hop ZF Beamforming for MIMO Full-Duplex Relaying With Co-Channel Interference

“…It is seen that the Monte Carlo simulations and presented mathematical formulas in (32) attain an accurate coincide which corroborates the precision of the presented accurate closed-form mathematical formula. Furthermore, the closeness of the considered lower-bound mathematical formula in (35) is confirmed, where it gets closer at high array gain and/or diversity order. Our analysis reveals a significant ergodic capacity improvement as a result of higher diversity order and/or high average per-hop SNR.…”

“…In dual-hop relaying systems, hop-by-hop MRT beamforming is utilized to steer the transmitted signal along the strongest eigenmode of each hop's channel (see e.g., [34], [35]). Hence, in the presence of perfect CSI of H 1 and H 2 , and in the absence of full CSI of H R , H, and G, the first hop MRT beamformers w S and w R are set to match v max H Note that MRT beamforming requires full CSI for H 1 , H 2 only, while ZF beamforming requires full CSI for H 1 , H 2 , H R , H, and G. Meanwhile, in the absence of H R , H, and G, ZF beamforming reduces to MRT beamforming.…”

Wireless Powered Dual-Hop Multi-Antenna Relaying Systems: Impact of CSI and Antenna Correlation

“…As a matter of fact, similar assumption has been widely adopted in SWIPT relaying literature with both single-antenna relay [17] and multi-antenna relay [35]. In addition, as in [17], [36], we assume that the relay is entirely powered via RF energy harvesting. By implementing multiple antennas at the relay, the energy harvesting efficiency can be significantly improved [4], [37], hence more energy can be harvested to support its power requirements.…”

Beamforming Design for Full-Duplex SWIPT with Co-Channel Interference in Wireless Sensor Systems

“…Due to aggressive frequency reuse in wireless sensor networks, receivers suffer from co-channel interferers (CCIs). Systems with SWIPT operating in the presence of CCIs have been considered in [ 18 , 19 , 20 , 21 , 22 ]. The work in [ 18 ] considered a transmission scheme for a two-user MIMO interference channel (IFC) system with energy harvesting.…”