## 2 Background and Related Work  
This section provides some background information on ad hoc networks, specifically on VANETs. While the primary objective of this paper is to investigate the impact of the signal strength in ad hoc networks on the performance of VANETs, a literature review of the existing research is also essential to establish a measurement framework and choose the analysis methods for the results. VANETs are provided as an important component of Intelligent Transportation Systems (ITS) especially for enhancing traffic safety [5; 6; 7]. The primary goal of VANETs is to improve the safety of drivers and passengers by facilitating the exchange of information between vehicles. VANETs can be considered an extreme form of mobile ad hoc networks (MANETs). While both MANETs and VANETs involve nodes communicating in an ad hoc manner without requiring fixed infrastructure, VANETs exhibit distinct characteristics [8; 9]. The network topology in VANETs undergoes frequent changes due to high-speed mobility, and vehicles typically move in specific directions within the network. [PERSON], [PERSON] et al. [10] investigated the existing Wi-Fi protocol for Vehicle-to-Vehicle (V2V) communications in high speed environments. They demonstrated that Wi-Fi can be used for vehicular communication at high speeds and suggested some useful applications. Moreover, VANET provides massive opportunities for online vehicle entertainment such as through the local ad hoc networks sharing pictures, video, files, gaming, and chatting. Figure 1 shows a typical VANET application scenario consisting of in-vehicle and roadside sensors, their positions, intersection maps, and both-way wireless communications. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Abbreviation** & **Definition** & **Abbreviation** & **Definition** \\ \hline AP & Access Point & ms & Milliseconds \\ AODV & Ad hoc On-demand Distance Vector & mW & Milliwatts \\ BSS & Basic Service Set & NLOS & Non-Line of Sight \\ CA & Collision Avoidance & OPNET & Optimized Network Engineering Tool \\ CICAS & Cooperative Intersection Collision & P2P & Peer-to-Peer \\  & Avoidance Systems Initiative & & \\ CPU & Central Processing Unit & PER & Packet Error Rate \\ CSMA & Carrier Sense Multiple Access & PCF & Point Coordination Function \\ dB & Decibel & PLCP & Physical Layer Convergence Protocol \\ dBm & dB-milliwatts & PMD & Physical Medium \\ DCF & Distributed Coordinated Function & PHY & Physical Layer \\ DSSS & Driving Safety Support Systems & OSI & Open Systems Interconnection model \\ EDCA & Enhanced Distributed Channel Access & QoS & Quality of Service \\ ESS & Extended Service Set & RF & Radio Frequency \\ FHSS & Frequency-Hopping Spread Spectrum & RSSI & Received Signal Strength Indicator \\ FSPL & Free-space Path Loss & RSU & Roadside Equipment \\ FTP & File Transfer Protocol & RWP & Random Way Point \\ GPS & Global Positioning System & SNR & Signal-to-Noise Ratio \\ IBSS & Independent Basic Service Set & SRD & Short Range Destination \\ ISM & Information Systems Management & SSID & Service Set Identifier \\ IR & Infrared & TCP & Transmission Control Protocol \\ ITS & Intelligent Transportation Systems & UDP & User Datagram Protocol \\ IVC & Inter Vehicular Communications & VANET & Vehicular Ad hoc Network \\ IWF & Information Warning Function & VCWS & Vehicle Collision Warning Systems \\ LAN & Local-Area Network & V2I & Vehicle to Infrastructure \\ LLC & Logical Link Control & V2R & Vehicle-to-Roadside \\ MAC & Medium Access Control & V2V & Vehicle-to-Vehicle \\ MANET & Mobile Ad hoc Network & WAVE & Wireless Access in Vehicular \\ MH & Map Hack & WDS & Wireless Distribution System \\ MPDU & MAC Protocol Data Unit & WLAN & Wireless Local-Area Network \\ mu & Microseconds & WMN & Wireless Mash Network \\ \hline \hline \end{tabular}
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Table 1: List of abbreviations used in this paper.