A smart grid combines a set of functionalities that can only be achieved through ubiquitous sensing and communication across the electrical grid. A heterogeneous communication applied through the adaptation of the Ubiquitous Sensor Network (USN) layered structure to Smart Grid has been proposed by the International Telecommunication Union (ITU). This paper presents the communications technologies which can be deployed within USN schematic layers for a secure and robust communication, together with a study of their pro's and con's. It also discusses the factors that can affect the selection of communication technologies and suggests possible communications technologies at different USN layers.