Energy-efficient AF OSTBC-MIMO systems for two-way relaying considering circuit energy consumption

Low energy consumption is being one of the most important criteria used by network designers to evaluate performances and ensure reliability of next-generation wireless communication systems. A framework for energy efficiency (EE) optimization in cooperative two-way Multiple Input Multiple Output (MIMO) systems with amplify-and-forward (AF) relaying and Orthogonal Space Time Block Code (OSTBC) under data rate constraint is studied in this paper. We evaluate the total consumed energy that includes both the transmitted energy and the circuit energy consumption. The energy minimization problem is written in a geometric form and then solved employing a useful optimization tool denoted as a Matlab solver for geometric programs in posynomial form (gpposy). The effect of antennas number and the relay´s position on the total energy consumption is also investigated through this work. Simulation results show that the proposed scheme decreases the total energy consumption compared to single antenna per node networks.