1,220 research outputs found
Wireless Information and Energy Transfer for Two-Hop Non-Regenerative MIMO-OFDM Relay Networks
This paper investigates the simultaneous wireless information and energy
transfer for the non-regenerative multipleinput multiple-output orthogonal
frequency-division multiplexing (MIMO-OFDM) relaying system. By considering two
practical receiver architectures, we present two protocols, time switchingbased
relaying (TSR) and power splitting-based relaying (PSR). To explore the system
performance limit, we formulate two optimization problems to maximize the
end-to-end achievable information rate with the full channel state information
(CSI) assumption. Since both problems are non-convex and have no known solution
method, we firstly derive some explicit results by theoretical analysis and
then design effective algorithms for them. Numerical results show that the
performances of both protocols are greatly affected by the relay position.
Specifically, PSR and TSR show very different behaviors to the variation of
relay position. The achievable information rate of PSR monotonically decreases
when the relay moves from the source towards the destination, but for TSR, the
performance is relatively worse when the relay is placed in the middle of the
source and the destination. This is the first time to observe such a
phenomenon. In addition, it is also shown that PSR always outperforms TSR in
such a MIMO-OFDM relaying system. Moreover, the effect of the number of
antennas and the number of subcarriers are also discussed.Comment: 16 pages, 12 figures, to appear in IEEE Selected Areas in
Communication
MIMO-OFDM Based Energy Harvesting Cooperative Communications Using Coalitional Game Algorithm
This document is the Accepted Manuscript version. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this paper, we consider the problem of cooperative communication between relays and base station in an advanced MIMO-OFDM framework, under the assumption that the relays are supplied by electric power drawn from energy harvesting (EH) sources. In particular, we focus on the relay selection, with the goal to guarantee the required performance in terms of capacity. In order to maximize the data throughput under the EH constraint, we model the transmission scheme as a non-transferable coalition formation game, with characteristic function based on an approximated capacity expression. Then, we introduce a powerful mathematical tool inherent to coalitional game theory, namely: the Shapley value (Sv) to provide a reliable solution concept to the game. The selected relays will form a virtual dynamically-configuredMIMO network that is able to transmit data to destination using efficient space-time coding techniques. Numerical results, obtained by simulating the EH-powered cooperativeMIMO-OFDMtransmission with Algebraic Space-Time Coding (ASTC), prove that the proposed coalitional game-based relay selection allows to achieve performance very close to that obtained by the same system operated by guaranteed power supply. The proposed methodology is finally compared with some recent related state-of-the-art techniques showing clear advantages in terms of link performance and goodput.Peer reviewe
Physical Layer Service Integration in 5G: Potentials and Challenges
High transmission rate and secure communication have been identified as the
key targets that need to be effectively addressed by fifth generation (5G)
wireless systems. In this context, the concept of physical-layer security
becomes attractive, as it can establish perfect security using only the
characteristics of wireless medium. Nonetheless, to further increase the
spectral efficiency, an emerging concept, termed physical-layer service
integration (PHY-SI), has been recognized as an effective means. Its basic idea
is to combine multiple coexisting services, i.e., multicast/broadcast service
and confidential service, into one integral service for one-time transmission
at the transmitter side. This article first provides a tutorial on typical
PHY-SI models. Furthermore, we propose some state-of-the-art solutions to
improve the overall performance of PHY-SI in certain important communication
scenarios. In particular, we highlight the extension of several concepts
borrowed from conventional single-service communications, such as artificial
noise (AN), eigenmode transmission etc., to the scenario of PHY-SI. These
techniques are shown to be effective in the design of reliable and robust
PHY-SI schemes. Finally, several potential research directions are identified
for future work.Comment: 12 pages, 7 figure
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