Wireless Powered Communication Networks (WPCN), which has attracted much attention of researchers, also been recently recommended in 5 th generation (5G) wireless networks. With the help of the WPCN, the reliability and battery life of wireless low-power devices can be improved. In this paper, we investigate throughput and ergodic capacity in WPCN-assisted amplify-and-forward (AF) relaying system, considering two transmission modes including delay-tolerant and delay-limited. As important achievement, we propose symmetric energy harvesting protocol, namely time power switching relaying (TPSR) in order to find maximal throughput. In particular, both time switching and power switching coefficients in this schemes are considered. Unlike most of the previous works, we further focus on impact of outdated channel state information (CSI) in this WPCN. In order to evaluate information processing efficiency, the performance can be substantially improved by optimally harvesting time and power coefficients of the received signal at relay node for energy and information extraction, and by deploying several scenarios. By deploying Monte Carlo simulation, it is confirmed that the system performance is more sensitive to CSI estimation error, noise variance, signal-to-noise ratio (SNR) and resulting in other reasonable computations of TPSR need be deployed to obtain QoS requirement.Keywords: channel state information; energy harvesting; amplify-and-forward; time power switching relaying; throughput
IntroductionRecently, the importance of harvested energy is widely recognized, when 5G cellular networks require high speed data and continuing operation. In [1], wireless powered communication network (WPCN) was presented the possibility of reliable data and wireless energy transfer technique in terms of interference channel. In principle, radio-frequency (RF) harvested energy is considered as a monotonous self-sustainability supply and it can use redundant power from ambient environment. In [2], the research results proved that the capacity can be enhanced even in the frequency-selective channels. Furthermore, in [1],[2] the receiver might encrypt the received signal and process energy collection in the same time slot. Unfortunately, the past works proved that it did not use to be applicable to receiver circuit technology, due to limitations of cheap capacitors.In addition, thanks to recent advancements of circuit, it is confirmed that WPCN is feasible, since the capability extending coverage range of relaying wireless network and then it combines with RF-based energy harvesting to become key factors of next generations wireless systems [3]- [9]. In