Toward Optimal Power Control and Transfer for Energy Harvesting Amplify-and-Forward Relay Networks

Abstract

In this paper, we study an amplify-and-forward (AF) relay network with energy harvesting (EH) source and relay nodes. Both nodes can continuously harvest energy from the environment and store it in batteries with finite capacity. Additionally, the source node is capable of transferring a portion of its energy to the relay node through a dedicated channel. The network performance depends on not only the energy arrival profiles at EH nodes but also the energy cooperation between them. We jointly design power control and transfer for maximizing the sum rate over finite time duration, subject to energy causality and battery storage constraints. By introducing auxiliary variables to confine the accumulated power expenditure, this non-convex problem is solved via a successive convex approximation (SCA) approach, and the local optimum solutions are obtained through dual decomposition. Also when channels are quasi-static and the power control values of the source (relay) node are preset to a constant, a monotonically increasing power control structure with the time is revealed for the relay (source) node with infinite battery capacity. Computer simulations are used to validate the theoretical findings and to quantify the impact of various factors such as EH intensity at nodes and relay position on the sum rate performance.

Time-Switching EH-Based Joint Relay Selection and Resource Allocation Algorithms for Multi-User Multi-Carrier AF Relay Networks

“…where P max is the source transmission power budget. 2 Further, constraint (C.1) and (C.2) ensure that each subcarrier in MA phase is paired with a subcarrier in the BC phase, (C.3) and (C.4) establish that each paired subcarrier is allocated to one-and-only-one user pair and relay node respectively, (C.5) mandates that the energy utilisation by relay nodes never exceed their harvested energy, and (C.6) bounds the network's transmit power regulation.…”

“…Therefore, to meet these requirements it is currently projected that by the end of 2030, there will be about 4 Gt (Gigatonnes) of CO 2 emissions by the information and communication (ICT) sector [1]. To achieve the greentarget for the environment, one effective way is to harvest energy from the ambient sources like solar, wind etc [2], [3] or radio-frequency (RF) signals. Another way is to design cellular networks with greater scrutiny towards energy-aware engineering and resource allocation policies that not only prolong the network's lifespan, but also contribute towards energy savings under the protection of green communications [1].…”

Joint Balanced Routing and Energy Harvesting Strategy for Maximizing Network Lifetime in WSNs

“…The strategy is a joint power control and energy transfer scheme to maximize the throughput by considering the energy causality constraints. In [33], an AF-RN with energy harvesting (EH) source and relay nodes is investigated. To consider the energy arrival profiles and the energy cooperation between EH nodes, a joint power control and transfer is designed to maximize the total data rate, subject to energy causality and battery storage constraints.…”

Full-Duplex Relaying for Opportunistic Spectrum Access Under an Overall Power Constraint

“…Indeed, even in the standard Gaussian relay channel, which is not impaired by multi-user interference, both DF and CF schemes achieve large rates than AF [16]. Second, AF relaying in multi-user networks has been investigated mostly in the multi-hop special case, in which the direct link between the user and its destination is negligible [17], [18], [19], [20], [21], [22], [23], [24], [25]. When the direct link is taken into account, as in our work, AF turns the channel into a channel with memory [16], under which the achievable rate regions have very complex expressions [26], [27] leading to highly non trivial optimization problems.…”