A Novel Power Allocation Algorithm for Minimizing Energy Consumption in D2D Communication Systems

Device to device (D2D) is becoming one of the critic technologies of green smart cities. The uplink power allocation is investigated, when D2D users reuse subchannels of cellular users. The overall goal lies in minimization of energy consumption under guarantee of required data transmission rate, which belongs to a nondeterministic polynomial (NP) hard optimization problem. After analysis, we find that the constraint has implicit monotonicity, so we introduce a new vector to transform it into a monotonic optimization problem. Then, the equivalence of the problem before and after transformation is proved. To search global optimal energy conservation solution, we design a novel power allocation algorithm based on principle of reverse polyblock approximation and prove its convergence. It is demonstrated that our proposal is able to reduce power consumption in comparison to the most advanced alternatives. The proposed algorithm can be used as a benchmark to evaluate other algorithms.