Two‐way relay networks with wireless power transfer: design and performance analysis

Abstract

This paper considers amplify-and-forward (AF) two-way relay networks, where an energy constrained relay node harvests energy from the received radio-frequency signal. Based on time switching (TS) receiver, we separate the energy harvesting (EH) phase and the information processing (IP) phase in time. In the EH phase, three practical wireless power transfer policies are proposed: 1) dual-source (DS) power transfer, where both sources transfer power to the relay; 2) single-fixed-source (SFS) power transfer, where a fixed source transfers power to the relay; and 3) single-best-source (SBS) power transfer, where a source with strongest channel transfers power to the relay. In the IP phase, a new comparative framework of the proposed wireless power transfer policies is presented in two bi-directional relaying protocols, known as multiple access broadcast (MABC) and time division broadcast (TDBC).To characterize the performance of the proposed policies, new analytical expressions are derived for the outage probability, the throughput, and the system energy efficiency. Numerical results corroborate our analysis and show: 1) the DS policy performs the best in terms of both outage probability and throughput among the proposed policies, 2) the TDBC protocol achieves lower outage probability than the MABC protocol, and 3) there exits an optimal value of energy harvesting time fraction to maximize the throughput. A pivotal conclusion is reached that the SBS policy offers an optimal tradeoff between performance and power consumption since SBS consumes the least power but offers a comparable performance to that of DS. Index TermsMultiple access broadcast, time division broadcast, two-way relay networks, wireless power transfer.

Outage Probability Analysis in Power-Beacon Assisted Energy Harvesting Cognitive Relay Wireless Networks

“…Throughput analysis of amplifyand-forward (AF) and decode-and-forward (DF) relaying systems was performed in [11] and [9], [12], respectively. In addition, several aspects associated with EH relay systems 2 Wireless Communications and Mobile Computing have been examined, including EH-based relaying networks in the presence of interference [13], EH-based cooperative systems with spatially random relays [14], relay selection for trade-off between quality of information transfer and average transferred energy [15], and two-way EH-based relay systems [16].…”

Multihop Capability Analysis in Wireless Information and Power Transfer Multirelay Cooperative Networks

“…Unlike the previous studies, Zhang and Chen [17] considered that the relay can harvest energy from source, destination, or joint source and destination and investigated the maximal throughputs of three wireless power transfer (WPT) schemes, respectively. Furthermore, to overcome the loss of spectral efficiency induced by oneway relaying and half-duplex relaying, two-way relaying [18][19][20] and full-duplex relaying [21][22][23] were introduced into SWIPT system, respectively. Instead of considering one relayassisted SWIPT cooperative system in the aforementioned works, the works of [24][25][26] investigated multirelay-assisted case and analyzed the outage probability and end-to-end rate, respectively.…”

“…In this scheme, it is assumed that there is no direct link between the transmitter and receiver of a path (this assumption is adopted by most of the previous studies [5,[15][16][17][18][19][20][21][22][23][24][25][26]), such as and +1 in Figure 1. Multiple relays harvest power and decode the information from the transmitter first and then cooperatively forward the information and power to the receiver.…”

Unified analysis of energy harvesting–based MIMO relay wireless systems over Nakagami‐m fading channels

“…The application of energy‐harvesting techniques to relay networks has been considered recently in the literature, eg, see previous studies . Nasir et al studied amplify‐and‐forward (AF) relaying systems where an energy‐constrained relay node harvests energy from the source signal for signal processing and information transmission.…”

“…They proposed two protocols, namely, time switching–based relaying (TSR) and power splitting–based relaying (PSR), for energy harvesting and signal processing at the relay and then analyzed the achievable throughput. An analysis of decode‐and‐forward (DF) relaying systems was performed in the works of Nasir et al and Hadzi‐Velkov et al Also, many aspects associated with energy‐harvesting relay systems have been investigated, such as, energy harvesting–based relaying networks in the presence of interference, energy‐harvesting cooperative systems with spatially random relays, full‐duplex relaying for energy‐harvested relay networks, relay selection, and two‐way relaying systems . However, it is noted that these research works focus only on either single‐antenna relaying system modes or Rayleigh fading channels.…”