International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-4, Issue-2, Feb- 2017] https://dx.doi.org/10.22161/ijaers.4.2.32 ISSN: 2349-6495(P) | 2456-1908(O) www.ijaers.com Page | 163 Channel Modeling and Analysis for Radio Wave Propagation in Vehicular Ad Hoc Network Raghda Nazar Minihi 1 , Haider M. AlSabbagh 2 Dept. of Electrical Engineering, College of Engineering, University of Basra, Basrah, Iraq Abstract—VANET is the basic technology of Vehicle Infrastructure Integration (VII). Vehicular Ad Hoc Network (VANET) is the network that is connecting a vehicle to the infrastructure (V2I) and vehicle to vehicle (V2V) via wireless manner to convey the information between them. Therefore analyzing influence such channels on the VANET system performance is crucial. This paper is conducted to model and analyze the channel for radio wave propagation with considering free space, two ray ground reflection and single knife edge diffraction. The received power, path loss and effect state of the communication sides whether is in moving stable are discussed. The direction of moving of the vehicles and location of obstacles are also taken into account for calculating the received power and path loss. Keywords—Vehicle to Vehicle (V2V), Channel model, Radio propagation models, path loss, Doppler Effect. I. INTRODUCTION In the recent years, the number of vehicles is continuous increasing that is lead to increase the number of accidents. Therefore, the percentage of death due to an accident is increasing. The VANET technology has great attention to increasing safety road and plays a considerable role in decreasing number of the accidents, traffic jam and time traveling [1, 2]. Whenever the carrier's medium between connections sides in VANET is a wireless connection, therefore analyzing the channel mode is not direct. The transmitted signal is passing through the channel to reach the destination side. The channel may include many obstacles, such as buildings, trees, and cars that are affected by the power of transmitted signal. So, the transmit power suffers from attenuation and delay due to such factors (obstacles), which turn on the received power to be decreasing. The transmitter may send a signal by multipath: one's path is the direct that connect the transmitter and receiver is called a line of side path (LOS), other's path that may reflect from ground or wall and then reach to the destination is called (NLOS). The signal, also, may be scattering due to obstacles that found in the road between Tx and Rx and then reach the strong power to the receiver, so this path is NLOS. The receiver received signal with different amplitudes and times of arrival due to such multipath [3, 4]. Radio wave may be propagated in all direction through sky mode and can travel through long distance. Therefore, radio wave may be used in the AM radio due to the AM radio need long distance propagation [5]. Authors in [6] discussed the path loss and the received power for different vehicle's distributions. The presented radio wave propagation models are for free space, two-ray ground, single knife edge diffraction and multi knife edge diffraction. In [7] authors compared between free space, two-ray ground reflection and shadowing model to finding which of them have the significant impact on throughput and packet loss results. In this paper, a model for radio wave propagation to free space, two-ray ground reflection and single knife edge diffraction is modeled and analyzed. The received power and path loss are discussed for multi-cases. Also, the state of the Tx and Rx are considered when Tx and Rx are moving and for fixed positions. The direction of moving is presented via Doppler Effect. The location of obstacles between Tx and Rx and reflection from the ground have affected the results of the received power and path loss with respect to the distance between Tx-Rx. This paper is organized as follows. Section 2 radio wave propagation model is analyzed. In Section 3 the results of received power and path loss are given and discussed. Section 4 concludes this paper. II. MODELING FOR RADIO WAVE PROPAGATION This section presents radio wave propagation models for containing three: free space, two-ray ground, and single knife-edge diffraction model which is based on that presented in [6, 8]. A. Free space model The distance between Tx and Rx sides is only affected on power of transmitted signal that travel on medium between connection sides. Whenever, the distance between connection sides increases, the received power decreases. The received power is given as: (1) 2 2 2 ) 4 ( d G P p f t r   