1. Wireless Network Taxonomy

1. Wireless Network Taxonomy


2.What Are Ad Hoc Networks?
An ad hoc network is a collection of wireless mobile nodes (or routers) dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration.
The routers are free to move randomly and organize themselves arbitrarily; thus, the network’s wireless topology may change rapidly and unpredictably.
Such a network may operate in a standalone fashion, or may be connected to the Internet. Multihop, mobility, and large network size combined with device heterogeneity, bandwidth, and battery power make the design of adequate routing protocols a major challenge.

Figure 1 Mobile ad hoc networks.

Unlike a fixed wireless network, wireless ad hoc or on-the-fly networks are characterized by the lack of infrastructure. Nodes in a mobile ad hoc network are free to move and organize themselves in an arbitrary fashion.






3. Difference between Cellular and Ad Hoc Wireless Networks
Table 1 gives the major dif ferences between cellular and ad hoc networks.

3. Applications of Ad Hoc Wireless Networks
The field of wireless networking emerges from the integration of personal computing, cellular technology, and the Internet. This is due to the increasing interactions between communication and computing, which is changing information access from “anytime, anywhere” to “all the time, everywhere.”
The following are the applications of ad hoc wireless networks:
• Community network
• Enterprise network
• Home network
• Emergency response network
• Vehicle network
• Sensor network
• Education
• Entertainment
• Coverage extension
• Commercial and civilian environments
4. Technical and Research Challenges
Mobile ad hoc networks pose several technical and research challenges that need to be addressed. Ad hoc architecture has many benefits, such as self-reconfiguration and adaptability to high variable mobile characteristics such as power and transmission conditions, traffic distributions, and load balancing. These benefits pose new challenges.
Challenges in Ad hoc Mobile Networks:
?Host is no longer an end system -can also be an acting intermediate system. No centralized entity –distributed
?Changing the network topology over time. How to support routing?
?Potentially frequent network partitions. How to support channel access?
?Every node can be mobile. How to deal with mobility?
?Limited power capacity. How to conserve power?
?Limited wireless bandwidth. How to use bandwidth efficiently?
?Presence of varying channel quality