Power Savings of Device-to-Device (D2D) Communication System Using Several Bands 5G Underlaying Cellular Networks

Device-to-device (D2D) communication, in contrast to typical cellular connections, is a direct connection between adjacent mobile users; it skips the base station (BS) and does not rely on network infrastructure to deliver high data rates and minimal battery usage. To address concerns regarding power consumption, D2D connections and cellular networks were combined in underlay mode. Both D2D and cellular connections employ licensed frequency bands in underlay D2D communication; however, due to resource sharing, these bands may overlap, reducing service quality while increasing spectral efficiency. Most existing research focuses solely on energy efficiency (EE) in the setting of individual cells. This article took into account the complete cellular network, including D2D connections across many bands. A closed-form expression for the energy EE of D2D connections underlaid on cellular networks over Nakagami-m fading channels has been derived using stochastic geometric theory, where performance improves by decreasing EE and EE decreases as the density of D2D and cellular users increases. Increasing the shape parameter value m (Nakagami-m order) on the D2D will improve users’ EE is also examined. Results of simulations are used to validate analytical conclusions.