Application of Non-Orthogonal Multiple Access for machine type communication in sub-terahertz band

摘要

There is a compelling need to address the problem of accommodating the rapidly growing number of machine type devices engaging in communication within the scarce radio spectrum, in current and forthcoming generations of wireless networks. The coming decades will also witness various novel applications, demanding wireless communication at very high data rate and energy efficiency, which currently favored technologies and techniques are inadequate to support. Because of these reasons, it seems inevitable that wireless communication will have to be facilitated by the efficient utilization of larger bandwidth at higher frequencies. Non-Orthogonal Multiple Access (NOMA) and shifting to higher frequency ranges such as the lower terahertz band, have been considered as solutions to provide space to the increasing number of communicating devices while meeting performance requirements. In this paper a machine type communication system model, utilizing the promising technique NOMA and operating in the sub-terahertz band, is developed and analyzed for its performances of data rate, spectral efficiency and energy efficiency. Thereafter the energy efficiency of the proposed model is optimized by using unconstrained optimization and then constrained (by threshold of data rate) optimization, the latter solving a multi-objective problem by the e-constraint method. The optimal transmission power is also derived for both optimization techniques. Finally, simulation results demonstrate that the energy efficiency can be maximized by utilizing unconstrained optimization and the spectral efficiency can be maximized by utilizing constrained optimization for both machine-to-machine and base-to-machine communications.