Placing the ‘third’ node: An energy efficiency perspective

Reduction of energy consumption has become one of the prime concerns in recently deployed wireless communication systems, both from ecological and from economical perspectives. This paper examines whether introduction of a third node, i.e. a wireless relay (R) placed between source node (S) and destination node (D), can improve the energy efficiency of the system. For collinear arrangement, a comparison of energy consumed per successful bit transmission reveals that energy saving is possible only when R is placed at a certain distance from S (or D) and there exists an optimum location where energy saving is maximum. For non-linear scenarios, however, the amount of energy saving depends on the two-dimensional co-ordinates of R. In this case, we have identified regions on the S-R-D plane that satisfies a given minimum energy saving constraint.