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Wireless Communications and Mobile Computing
Volume 2017, Article ID 6519709, 11 pages
Research Article

Nonoverlay Heterogeneous Network Planning for Energy Efficiency

Electrical and Electronics Engineering, Bahçeşehir University, Istanbul, Turkey

Correspondence should be addressed to Alkan Soysal; rt.ude.uab.gne@lasyos.nakla

Received 27 July 2016; Revised 27 December 2016; Accepted 22 January 2017; Published 9 February 2017

Academic Editor: Simone Morosi

Copyright © 2017 Mahmut Demirtaş and Alkan Soysal. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this paper, we introduce nonoverlay microcell/macrocell planning that is optimally designed for improving energy efficiency of the overall heterogeneous cellular network. We consider two deployment strategies. The first one is based on a fixed hexagonal grid and the second one is based on a stochastic geometry. In both of our models, microcells are placed in those areas where the received signal power levels of macrocell common pilot channels are below a certain threshold. Thus, interference between microcells and macrocells is minimized. As a result, addition of microcells increases the achieved number of bits per unit energy. Under such deployment assumptions, we investigate the effects of certain parameters on the energy efficiency. These parameters include the user traffic, the Intersite Distance (ISD), the size of microcells and the number of microcells per macrocell for the grid model, and macrocell density and microcell density for the stochastic model. The results of our performance analyses show that utilizing microcells in a sparse user scenario is worse for the energy efficiency whereas it significantly improves both energy and spectral efficiencies in a dense user scenario. Another interesting observation is that it is possible to choose an optimum number of microcells for a given macrocell density.