Traditional omni-directional wireless sensor networks (WSNs) are commonly modeled as directed graphs. Sensor devices have a limited battery; thus, reducing energy consumption by topology control is a crucial problem. It is a great challenge to obtain this goal.

The paper consists of nine sections. Sections 1 and 2 give necessary preliminaries: an introduction and problem formulation of the antenna orientation (AO) as well as the antenna orientation and power assignment (AOPA). Section 3 shows that both the AO and AOPA problems are NP-hard. However, the authors attempt to show algorithms for finding solutions: sections 4 (bottom-up approach) and 5 (top-down approach) for the AO problem, and section 6 (bottom-up and top-down approaches) for the AOPA problem. Section 7 gives proof for the worst-case lower bound for the stretch factor of the resulting network. Section 8 provides a performance analysis and experimental results, including a complexity analysis of the proposed algorithms. Section 9 presents conclusions.

Read this paper if you are looking for interesting and valuable results that can be easily used in WSN modeling.