Joint power allocation solutions for power consumption minimization in coordinated transmission system

The growth in energy consumption followed with global warming provides new topics and issues in communication systems known as green radio. Hence, how to reduce power consumption while meeting system throughput requirement is an urgent task. In this paper, we investigate a new cooperative power allocation scheme for a multi-user orthogonal frequency division multiplex (OFDM) system, in which two coordinated transmission points (CTP) jointly allocate their power to multiple orthogonal subchannels. In order to minimize the overall transmit power consumption while meeting the system total throughput requirement and also each CTP´s power constraint, we formulate the objective task into a constrained optimization problem and derived a group of closed form power allocation solutions. The solutions turn out to take the form of traditional water-filling (WF) and also have a cooperative feature. Based on the derived solution, a novel power allocation algorithm with joint minimization power consumption (JMPC-PA) is proposed. Numerical results are presented to verify the optimality of the derived scheme. Considering the flexibility of CTP´s category, e.g., base station or relay station, it is known that the derived scheme can be valid for any coordinated networks such as next-generation cellular networks or ad-hoc networks.