Int. J. Electron. Commun. (AEÜ) 68 (2014) 944–950 Contents lists available at ScienceDirect International Journal of Electronics and Communications (AEÜ) j ourna l h omepage: www.elsevier.com/locate/aeue Near ground propagation model for pine tree forest environment Osman Kurnaz a,b , Selcuk Helhel a,c,∗ a Akdeniz University, Engineering Faculty, Electrical and Electronics Engineering Department, Konyaaltı, Antalya, Turkey b The Scientific and Technological Research Council of Turkey (TUBITAK), National Metrology Institute, Gebze, Kocaeli, Turkey c The Scientific and Technological Research Council of Turkey (TUBITAK), National Observatory, Antalya, Turkey a r t i c l e i n f o Article history: Received 5 March 2013 Accepted 21 April 2014 Keywords: Free space path loss Near ground plane earth model Radio propagation Trunk height gain Radio propagation terrain factors a b s t r a c t A propagation model experimentally derived from both free space and near ground plane earth path loss models for pine tree forest with foliage depth lower than 400 m has been proposed. It is a piecewise model taking foliage depth of 200 m as a boundary. The model is compared with several well-known models, namely Weissberger, ITU-R and COST235. Different from other models, the proposed one takes into account trunk height gain k. Observed average error is about 6 dB for proposed model whereas it is about 32 dB, 16 dB and 20 dB for COST235, Weissberger and ITU-R models, respectively. Also, it is observed that COST235 estimates the highest path loss among the models and it has the highest absolute errors especially in a forest with low foliage density. © 2014 Elsevier GmbH. All rights reserved. 1. Introduction New wireless technologies rapidly grow resulting in an increase in popularity of mobile communication. This popularity requires that development of a proper propagation model is essential for uninterrupted communication in both urban and unsettled areas including forests and hilly territories. Use of a proper model is not only required for personal cell phone communication but also vital for military, governmental and unmilitary personal radiotelephone communication especially in forest areas. These requirements force scientists to investigate propagation mechanisms in forested area [1–6]. Meng et al. [1] proposed a modified ITU-R model taking into account the lateral wave effect. Their modified model was verified using measured and published data, and found to have higher accu- racy for large foliage depth in the VHF band as compared to current models. Dias et al. [2] investigated a measurement campaign of land mobile HF/VHF radio signal in a typical urban sample of the Brazilian Atlantic Rainforest. They compared their measurements with calculated values from Tamir’s model [7] in order to assess its variation with frequency and distance, and confirmed the good performance of Tamir’s model. Azevedo and Santos [6] proposed a model developed from an extensive measurement campaign carried out for different ∗ Corresponding author at: Akdeniz University, Engineering Faculty, Electrical and Electronics Engineering Department, Konyaaltı, Antalya, Turkey. Tel.: +90 242 310 6393; fax: +90 242 310 6306. E-mail addresses: selcukhelhel@akdeniz.edu.tr, helhelselcuk@gmail.com (S. Helhel). vegetation densities and types of trees. They pointed out the importance of the vegetation density in addition to distance and frequency effect on path loss calculation, and included a compar- ison with other methods in order to evaluate the performance of the model. The foliage loss models proposed so far [1–7] present general formulas for wide frequency ranges and applications. Although they estimate path loss within an acceptable error margin for gen- eral conditions, they fail for specific conditions. Most of the forested areas in Turkey are covered by pine trees, and there are civil and governmental based issues which require development of specific propagation models. This requirement motivated us to generate a new model for such an environment where personal or vehicular communication is necessary. Therefore, only antenna heights of 2 m and only three frequencies, GSM900, GSM1800 and CDMA2100, have been examined. In this study, the procedure of new model development has been presented starting with plane earth measurements. In Sec- tion 2, theoretical background is given. In Section 3, test setup and measurement campaign are described. In Section 4, comparison of the proposed model with Weissberger [4], ITU-R [8] and COST235 [9] models has been presented. This is followed by conclusion in Section 5. 2. Theoretical background 2.1. Free space and plane earth path loss models In radio wave propagation, path loss gives an important idea about performance of a system. The free space path loss model can be used as a lower bound [1] to estimate path loss. http://dx.doi.org/10.1016/j.aeue.2014.04.019 1434-8411/© 2014 Elsevier GmbH. All rights reserved.