Energy harvesting aided device-to-device communication networks

Abstract

With the ever growing demands of power and bandwidth by users, energy and spectral efficiency emanated as key criteria for designing future wireless networks. Therefore, in this thesis energy harvesting (EH) aided device-to-device (D2D) communication is designed for improving both the key design criteria, which is an intricate journey from the realm of individual analysis of EH and D2D communication to that of amalgamating the two techniques.
Specifically, with the widespread use of energy hungry smart devices, these devices become dis-functional due to outage of batteries, which can be avoided by introduction of EH capability at these nodes. In this context, an energy efficient successive relaying based network is conceived using rechargeable source and relay nodes having limited buffers for both their energy and data storage. An optimal and sub-optimal transmission policies are designed for the maximisation of the network throughput with non-causal knowledge of energy arrivals by the deadline.
On the other hand, for exploiting the spectrum efficiently, D2D communication is invoked which brings in new interference scenarios that may be circumvented by incorporating fractional frequency reuse (FFR) or soft frequency reuse (SFR) in OFDMA cellular networks. By carefully considering the downlink resource reuse of the D2D links, beneficial frequency allocation schemes are proposed, when the macrocell has employed FFR or SFR. The coverage probability and the capacity of D2D links are analytically derived under the proposed schemes.
It is imperative to integrate the benefits of EH and D2D communication aided systems for creating unparalleled opportunities in emerging applications. Therefore, a system is designed that comprises of EH aided D2D links relying on downlink resource reuse with the goal of maximizing the sum-rate of the D2D links, without degrading the quality of service (QoS) requirement of the MUs. A pair of joint resource block and power allocation algorithms are proposed for the D2D links, when there is non-causal (off-line) and causal (on-line) knowledge of the EH profiles at the D2D transmitters.
For the sake of further accentuating design flexibility and alleviating the demands of increased spectral resources, previously designed EH aided D2D communication is investigated in conjunction with heterogeneous network (HetNet). An algorithmic solution is proposed with the aim of maximising the sum-rate of these D2D links in the downlink of two-tier HetNet without unduly degrading MU’s throughput, when two tiers share spectrum under following regimes: (a) orthogonal, (b) co-channel and (c) the proposed coorthogonal. Low complexity heuristic methods are also proposed, which demonstrate that the optimization of the D2D-MU matching is indeed crucial for the system considered.

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ORCID for Lajos Hanzo: orcid.org/0000-0002-2636-5214

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