Research Article Impact of Dynamic Path Loss Models in an Urban Obstacle Aware Ad Hoc Network Environment Kashif Amjad, 1 Muhammad Ali, 2 Sohail Jabbar, 1,3 Majid Hussain, 3 Seungmin Rho, 4 and Mucheol Kim 4 1 Department of Computer Science, Bahria University, Islamabad 44000, Pakistan 2 Department of Electrical Engineering, COMSATS Institute of Information Technology, Islamabad 44000, Pakistan 3 Department of Computer Science, COMSATS Institute of Information Technology, Sahiwal 57000, Pakistan 4 Department of Multimedia, Sungkyul University, Anyang-si 430-742, Republic of Korea Correspondence should be addressed to Mucheol Kim; mucheol.kim@gmail.com Received 2 December 2014; Accepted 3 February 2015 Academic Editor: Yasuko Y. Maruo Copyright © 2015 Kashif Amjad et al. his 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. his study highlights the importance of the physical layer and its impact on network performance in Mobile Ad Hoc Networks (MANETs). his was demonstrated by simulating various MANET scenarios using Network Simulator-2 (NS-2) with enhanced capability by adding propagation loss models (e.g., modiied Two-Ray Ground model, ITU Line of Sight and Nonline of Sight (ITU-LoS and NLoS) model into street canyons and combined path loss and shadowing model (C-Shadowing)). he simulation results were then compared with the original Two-Ray Ground (TRG) model already available into NS-2. he scenario primarily simulated was that of a mobile environment using Random Way Point (RWP) mobility model with a variable number of obstacles in the simulation ield (such as buildings, etc., causing variable attenuation) in order to analyze the extent of communication losses in various propagation loss models. Performance of the Ad Hoc On-demand Distance Vector (AODV) routing protocol was also analyzed in an ad hoc environment with 20 nodes. 1. Introduction Mobile Ad Hoc Networks are formed by a collection of mobile nodes that can establish wireless communication links among each other without any infrastructure. his feature gives such networks a distinguished edge over other networks (such as GSM, UMTS, CDMA, and LTE). However it also brings new challenges and performance compromises (in terms of reliability, quality of service, scalability, etc.). Up until today, the majority of published research in MANETs has used simulation tools as a prime mean for performance analysis. his is primarily due to the high cost involved in realization of real ad hoc test beds. NS-2 [1] is the most popular simulation tool in MANETs researcher commu- nity [2]. his tool accommodates various routing, mobility, and propagation features key to analyze the performance of MANETs. However, this tool considers lat terrain for simulation and does not accommodate geographical features of the simulation ield that may afect the received signal strength at the receiver. In [3], the author has introduced specialized mobility models, which restrict the mobility of nodes due to obstacles in the simulation area and some variations have been suggested in [4] for NS-2 environment. However the focus of their work is mainly the mobility aspect of the nodes. Contrarily, a vast majority of simulation studies have used simplistic radio propagation models [5] such as Two-Ray Ground (TRG) for performance analysis of MANETs routing strategies, which results in more opti- mistic rather than realistic network performance. his study accommodates several new propagation models (i.e., ITU Line of Sight (LoS) and Nonline of Sight (NLoS) path loss models in street canyons [6], and combined shadowing- path loss model [7] along with modiied-TRG model) in an obstacle aware mobility environment. By varying the number of obstacles in the simulation ield, the performance of Ad Hoc On-Demand Distance Vector (AODV) routing protocol Hindawi Publishing Corporation Journal of Sensors Volume 2015, Article ID 286270, 8 pages http://dx.doi.org/10.1155/2015/286270