Energy Efficient Resource Allocation in Machine-to-Machine Communications with Multiple Access and Energy Harvesting for IoT

摘要

This paper studies energy efficient resource allocation for amachine-to-machine (M2M) enabled cellular network with non-linear energyharvesting, especially focusing on two different multiple access strategies,namely non-orthogonal multiple access (NOMA) and time division multiple access(TDMA). Our goal is to minimize the total energy consumption of the network viajoint power control and time allocation while taking into account circuit powerconsumption. For both NOMA and TDMA strategies, we show that it is optimal foreach machine type communication device (MTCD) to transmit with the minimumthroughput, and the energy consumption of each MTCD is a convex function withrespect to the allocated transmission time. Based on the derived optimalconditions for the transmission power of MTCDs, we transform the originaloptimization problem for NOMA to an equivalent problem which can be solvedsuboptimally via an iterative power control and time allocation algorithm.Through an appropriate variable transformation, we also transform the originaloptimization problem for TDMA to an equivalent tractable problem, which can beiteratively solved. Numerical results verify the theoretical findings anddemonstrate that NOMA consumes less total energy than TDMA at low circuit powerregime of MTCDs, while at high circuit power regime of MTCDs TDMA achievesbetter network energy efficiency than NOMA.