Energy harvesting for wireless communication networks is a new paradigm that allows terminals to recharge their batteries from external energy sources in the surrounding environment. A promising energy harvesting technology is wireless power transfer where terminals harvest energy from electromagnetic radiation. Thereby, the energy may be harvested opportunistically from ambient electromagnetic sources or from sources that intentionally transmit electromagnetic energy for energy harvesting purposes. A particularly interesting and challenging scenario arises when sources perform simultaneous wireless information and power transfer (SWIPT), as strong signals not only increase power transfer but also interference. This paper provides an overview of SWIPT systems with a particular focus on the hardware realization of rectenna circuits and practical techniques that achieve SWIPT in the domains of time, power, antennas, and space. The paper also discusses the benefits I. Krikidis is with the

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In this paper, we investigate resource allocation algorithm design for multicarrier non-orthogonal multiple access (MC-NOMA) systems employing a full-duplex (FD) base station (BS) for serving multiple half-duplex (HD) downlink (DL) and uplink (UL) users simultaneously. The proposed algorithm is obtained from the solution of a non-convex optimization problem for the maximization of the weighted sum system throughput. We apply monotonic optimization to develop an optimal joint power and subcarrier allocation policy. The optimal resource allocation policy serves as a system performance benchmark due to its high computational complexity. Furthermore, a suboptimal iterative scheme based on successive convex approximation is proposed to strike a balance between computational complexity and optimality. Our simulation results reveal that the proposed suboptimal algorithm achieves a closeto-optimal performance. Besides, FD MC-NOMA systems employing the proposed resource allocation algorithms provide a substantial system throughput improvement compared to conventional HD multicarrier orthogonal multiple access (MC-OMA) systems and other baseline schemes. Also, our results unveil that the proposed FD MC-NOMA systems achieve a fairer resource allocation compared to traditional HD MC-OMA systems. ). Zhiguo Ding is with the School of Computing and Communications, Lancaster University, United Kingdom (email: z.ding@lancaster.ac.uk). This paper has been accepted in part for presentation at IEEE Globecom 2016 [1]. 2 I. INTRODUCTIONMulticarrier multiple access techniques have been widely adopted in broadband wireless communication systems over the last decade, due to their flexibility in resource allocation and their ability to exploit multiuser diversity [2]- [5]. In conventional multicarrier systems, a given radio frequency band is divided into multiple orthogonal subcarriers and each subcarrier is allocated to at most one user to avoid multiuser interference (MUI). The spectral efficiency of such systems can be improved significantly by performing joint user scheduling and power allocation. In [3], the authors studied the resource allocation algorithm design for energy-efficient communication in multi-cell orthogonal frequency division multiple access (OFDM) systems. In [4], an asymptotically optimal power control and subcarrier allocation algorithm was proposed to maximize the transmission rate in OFDM systems with multiple relays. The authors of [5] proposed a distributed subcarrier, power, and rate allocation algorithm for the maximization of the weighted sum throughput of relay-assisted OFDM systems. However, even with the schemes proposed in [3]-[5], the spectral resources are still underutilized as some subcarriers may be assigned exclusively to users with poor channel conditions to ensure fairness in resource allocation.Non-orthogonal multiple access (NOMA) has recently received significant attention since it enables the multiplexing of multiple users simultaneously utilizing the same frequency resource, which improves s...

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Multiple antenna technologies have attracted much research interest for several decades and have gradually made their way into mainstream communication systems. Two main benefits are adaptive beamforming gains and spatial multiplexing, leading to high data rates per user and per cell, especially when large antenna arrays are adopted. Since multiple antenna technology has become a key component of the fifth-generation (5G) networks, it is time for the research community to look for new multiple antenna technologies to meet the immensely higher data rate, reliability, and traffic demands in the beyond 5G era. Radically new approaches are required to achieve orders-of-magnitude improvements in these metrics. There will be large technical challenges, many of which are yet to be identified. In this paper, we survey three new multiple antenna technologies that can play key roles in beyond 5G networks: cellfree massive MIMO, beamspace massive MIMO, and intelligent reflecting surfaces. For each of these technologies, we present the fundamental motivation, key characteristics, recent technical progresses, and provide our perspectives for future research directions. The paper is not meant to be a survey/tutorial of a mature subject, but rather serve as a catalyst to encourage more research and experiments in these multiple antenna technologies. Index Terms-Beyond 5G, cell-free massive MIMO, beamspace, intelligent reflecting surface. I. INTRODUCTION T HE demand for higher data rates and traffic volumes seems to be never-ending, thus the quest for delivering The work of J.