Charge-Then-Cooperate Secure Resource Allocation for Wireless-Powered Relay Networks with Wireless Energy Transfer
ABSTARCT :
This correspondence studies resource allocation for a wireless-powered relay network, where a hybrid relay with constant energy supply assists an energy-constrained source to send confidential information to a destination in the presence of an eavesdropper. We propose a novel transmission protocol termed charge-then-cooperate to support secure communications in this network. Specifically, the hybrid relay charges the source in the energy transfer phase; then it forwards the confidential information from the source to the destination and concurrently injects jamming signals to combat eavesdropping. We aim to maximize the secrecy rate of the system via a joint optimization of power allocation and time assignment. To solve the formulated highly non-convex problem, we develop an efficient two-layer optimization algorithm that involves the one-dimensional search, the alternating optimization method, the successive convex approximation technique, and the Lagrange duality method. Simulation results demonstrate that the proposed scheme can guarantee a satisfactory secrecy rate.
EXISTING SYSTEM :
? The newly emerging wireless powered communication network (WPCN) is another line of WPT where ambient RF signals are used to power wireless devices .
? An important application for WPCN lies in relay-assisted WPCN (R-WPCN), where relays are used to assist information transmission in R-WPCN.
? In this paper, we consider a new R-WPCN consisting of multiple source-destination pairs assisted by a single hybrid relay node (HRN).
? One line of WPT focuses on so-called simultaneous wireless information and power transfer (SWIPT), where the same RF signal carries both energy and information at the same time.
DISADVANTAGE :
? These fundamental differences in the system model lead to an entirely different problem formulation than the one in.
? The original optimization problem is non-convex due to the unknown set of SUs that can successfully decode PU data and the product of optimization variables.
? But, for a fixed decoding set and with change of variables, the problem reduces to a convex problem.
? Then, we provide an iterative algorithm to obtain the global optimal solution of the original non-convex problem.
? Although the joint optimization problem in is non-convex, the problem structure is utilized to obtain a globally optimal solution.
PROPOSED SYSTEM :
• Due to the practical limitation of receivers that the received signals cannot be used to perform energy harvesting and information decoding simultaneously, two practical receiver architectures, namely time switching (TS) and power splitting (PS), were proposed in.
• We propose efficient algorithms to find the optimal solutions. In addition, suboptimal algorithms are proposed for both schemes to tradeoff the complexity and performance.
• We provide extensive numerical results to evaluate the performance of the proposed algorithms.
• Compared with EEA and ERA, we can see that the proposed optimal and suboptimal algorithms achieve better performance.
ADVANTAGE :
? We present simulation results to evaluate the performance of the proposed WP-CCRN scenario for the four resource allocation schemes, namely, STORA, ETA, MTM, and PTA schemes, against different system parameter.
? Compares the performance of the STORA scheme with that of the best SU selection (BSS), the random single SU selection (RSS-S), and the random multiple SUs selection (RSS-M).
? But, this consumes extra energy from the grid, reducing energy efficiency (EE) compared to the case of harvesting energy from PU transmissions only.
? We proceed in this direction by first proving the following lemma, which will be used in the proof of Proposition.
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