Connectivity Mode Management for User Devices in Heterogeneous D2D Networks

Device-to-Device (D2D) paradigm is one of the key enablers for boosting the energy efficiency (EE) of networks. For the actualization of EE in multi-mode heterogeneous D2D networks, resource allocation should be executed accordingly. In that regard, we study resource allocation management in heterogeneous D2D networks where there is a LEO satellite and a cellular base station (BS) with multi-mode user devices (satellite, BS and D2D connectivity modes) dispersed in the terrestrial cell. We formulate the EE optimization of mode selection constrained by a designated total network service capacity threshold. We also implement a sub-optimal pattern search algorithm (PSA) with the aim of enhancing EE while keeping total system service capacity at an acceptable level and compare it to alternative resource management schemes. Based on our simulation results, PSA achieves the most beneficial EE value in contrast to other schemes while still managing to meet the goodput threshold. Additionally, we discuss the multi-mode nature of our heterogeneous network from EE and goodput perspectives.