Wireless Networks Based on WiFi and Related Technologies

Wireless Networks Based on WiFi and Related Technologies

Rajendra V. Boppana (University of Texas at San Antonio, USA) and Suresh Chalasani (University of Wisconsin-Parkside, USA)
Copyright: © 2009 |Pages: 16
DOI: 10.4018/978-1-60566-094-3.ch017


Multihop wireless networks based on WiFi technology offer flexible and inexpensive networking possibilities. Applications of multihop wireless networks range from personal networks within consumer homes to citywide departmental networks to wide-area vehicular ad hoc networks. In this chapter, we focus on multihop ad hoc networks with communication among user devices and access points, where available, without the restriction that the user devices need to be within the radio range of access points. We first describe pure WiFi networks and their limitations. Next we discuss mixed networks based on WiFi and other wired and wireless technologies to provide robust city-scale networks. This chapter also explores security issues and vulnerabilities of wireless networks. An emerging application of WiFi ad hoc networks-RFID (radio frequency identification) networks based on the WiFi technology for warehouses and large retail stores-is presented. This chapter also presents another emerging application of WiFi-based networks: vehicular ad hoc networks for automobiles.
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Ad Hoc Wireless Networks

An ad hoc wireless network is an impromptu network formed by several wireless devices, such as PDAs, laptops, and phones, without relying on an existing network infrastructure (Perkins, 2000). These devices (denoted as nodes) may be mobile and use a common wireless technology such as WiFi. To facilitate communication among the nodes that are not directly in the radio range of one another, the other nodes act as intermediate routers, just like routers in the Internet. Such networks are useful in military combat situations, where a group of soldiers must be connected to exchange information, or in emergency rescue operations, where there is no network infrastructure or the existing infrastructure has been destroyed. Because of frequent topology changes due to node mobility and due to wireless interference, the existing networking software used for the Internet is not suitable for these ad hoc networks. Consequently, extensive research on routing protocols and transport protocols has been conducted to make ad hoc networks suitable for general-purpose use.

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